Will Russia capture all of Kostyantynivka by December 31, 2026?

- [2026-07-03/04] Russia's MoD and Putin publicly claimed "full capture" of Kostyantynivka; Ukraine's General Staff and Zelensky rejected the claim, and ISW assessed Russian presence was limited to small sabotage/reconnaissance groups with Ukrainian forces still controlling most of the city. Ukraine still controls the strategically important eastern city of Kostiantynivka, President Volodymyr Zelensky and the General Staff said on Saturday, rejecting Russian claims that it has been captured... Russia's military told President Vladimir Putin on Friday that its forces had taken control of Kostiantynivka. https://www.themoscowtimes.com/2026/07/04/zelensky-denies-russian-capture-of-key-eastern-city-kostiantynivka-a93165 - [2026-07-08] ISW reported no further Russian advance despite claims; a Ukrainian brigade commander reported repeated failed mechanized assaults continued offensive operations near and southwest of Kostyantynivka... but did not advance (pattern consistent through September). https://en.wikipedia.org/wiki/Battle_of_Kostiantynivka - [2026-07-18/20] Ukraine's 425th Skelya Regiment conducted a "flag-raising" operation in the city center, later captured by Russian forces; control of the city remained contested per ISW as of July 22. https://en.wikipedia.org/wiki/Battle_of_Kostiantynivka - [2026-08-23] Zelensky claimed Russian forces suffered 267,000 casualties front-wide since the start of 2026, with 70-80% of losses occurring in the Kostyantynivka direction, underscoring the grinding, inconclusive nature of the fight. https://en.wikipedia.org/wiki/Battle_of_Kostiantynivka - [2026-09-12] ISW noted Russian forces continued operations in the Kostyantynivka-Druzhkivka direction but did not advance , with efforts shifting toward Druzhkivka via Raiske, southwest of Druzhkivka. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-12-2026 - [2026-09-21/22] ISW's daily assessment stated Russian forces continued offensive operations near and southwest of Kostyantynivka on September 21 and 22 but did not advance, while milbloggers claimed Russian forces are shifting focus toward Oleksiievo-Druzhkivka via Kostyantynivka. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-22-2026 - [2026-09-25/26] ISW reported Russian forces recently advanced in western Kostyantynivka... indicating that there are likely no Ukrainian positions in the area, suggesting incremental Russian gains in the western part of the city. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-26-2026 - [2026-09-28] ISW reported Ukrainian forces counterattacked from several directions including west of Kostyantynivka and near Oleksiievo-Druzhkivka, indicating that Ukrainian forces cleared Russian infiltrators from Raiske on a prior date... counterattacked near Raiske, Toretske, and Novomykolaivka... to prevent Russian forces from encircling Druzhkivka from the southwest... also counterattacked from Oleksiievo-Druzhkivka, near Kurtivka, and west of Kostyantynivka. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-28-2026 - [2026-09-29] ISW's latest available report states Russian forces continued offensive operations in and southwest of Kostyantynivka and south and southeast of Druzhkivka on September 28 to 29, as Ukrainian forces counterattacked in the area , confirming the city remains contested with active Ukrainian resistance. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-29-2026-6abc6f16de2f1 - [2026-09-22] Separately, ISW assessed that Russia's MoD falsely claimed to have encircled nearby Dobropillya, part of a broader Kremlin "cognitive warfare" pattern of exaggerated claims around the Fortress Belt (including past false Kostyantynivka "capture" claims), which ISW found unsupported by battlefield evidence. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-22-2026 - [2026-09-22] At the sidelines of UNGA, Zelensky and Trump both expressed willingness to end the war, with Trump saying Russia and Ukraine "are going to make a deal," though no ceasefire or settlement terms affecting Kostyantynivka's status have been finalized. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-22-2026 - [2026-09-01 approx] Per Wikipedia's Battle of Kostiantynivka summary, as of early September Russia had only consolidated small portions (roughly 12-15% as of June, with incremental gains since) and the city remains a contested "grey zone," not shaded entirely under ISW's "Assessed Russian-Controlled Terrain" or "Assessed Russian Advances" layers. https://en.wikipedia.org/wiki/Battle_of_Kostiantynivka BOTTOM LINE: As of the most recent ISW assessment (September 29, 2026), Kostyantynivka remains a contested battleground with ongoing Russian infiltration/offensive operations and active Ukrainian counterattacks (including recent Ukrainian successes clearing infiltrators near Druzhkivka); Russia has made only incremental, localized gains (e.g., western Kostyantynivka) and has not achieved — nor does ISW show — full control of the city on its map, making a "Yes" resolution by December 31, 2026 currently unconfirmed and historically over-claimed by Russian officials. NOT FOUND: An explicit current ISW percentage-of-control figure for Kostyantynivka as of late September 2026 (ISW stopped publishing precise percentages after mid-2026); any DeepStateMap-specific recent snapshot of Kostyantynivka control; confirmation of any negotiated-settlement terms specifically addressing Kostyantynivka's territorial status.

- [2026-01-28/02-25] Reference case: Pokrovsk — Russia began frontal assaults in March 2024 and ISW assessed Russian forces started their drive toward Pokrovsk in February 2024 and did not seize most of Pokrovsk until December 2025 — 21 months after starting frontal assaults , with full control (incl. Myrnohrad) only confirmed by late January/February 2026 (https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-february-25-2026). - [2024-02-17] Reference case: Avdiivka — Russia captured Avdiivka on February 17, 2024 after a four-month assault , a smaller and less fortified settlement than Kostiantynivka (https://ukraine-war-analytics.com/battles/avdiivka-fall-2024.html). - [2025-10-25] Battle of Kostiantynivka formally began (first infiltration attempts) after Russia's August 2025 capture of Toretsk; ISW/Wikipedia track this as an ongoing, distinct battle (https://en.wikipedia.org/wiki/Battle_of_Kostiantynivka). - [2026-06-10] ISW assessed Russia had first infiltrated the city in October 2025 and have since entered roughly 12.69 percent of it , and separately noted Russian forces missed their command's deadline to seize the city by May 2026 (https://united24media.com/war-in-ukraine/russia-shifts-donetsk-offensive-to-kostyantynivka-after-slovyansk-push-stalls-isw-says-19731). - [2026-07-03/04] Putin/Peskov publicly claimed full capture (" The city is now entirely under our control "), but ISW and Ukraine's General Staff rejected this, with ISW saying Russian forces have achieved tactical gains in Kostiantynivka in recent weeks, but their presence in the city remains limited to small sabotage and reconnaissance groups, while Ukrainian forces continue to hold positions there (https://english.nv.ua/russian-war/isw-rejects-putin-s-claim-of-full-capture-of-kostiantynivka-50621667.html). - [2026-07-11] Washington Times reported that after Russia's capture claim, the Institute for the Study of War said Russian forces continued infiltration and consolidation operations after the Kremlin announced the city's capture... and described the announcement as part of an information campaign (https://www.washingtontimes.com/news/2026/jul/11/russia-says-kostiantynivka-fallen-ukrainian-troops-inside-city-tell/). - [2026-07-31] ISW/UATV reiterated no full capture: Russian forces have not established control over Kostiantynivka... heavy urban fighting continues throughout the city, where Russian troops are using small sabotage and assault groups to infiltrate different neighborhoods... Ukrainian and Russian positions remain intermingled, with the front line shifting frequently (https://uatv.ua/en/isw-russia-has-not-captured-kostiantynivka-despite-intensifying-pressure/). - [2026-07-31] Al Jazeera: as recently as three weeks ago, ISW estimated Russian forces had a presence in just 37 percent of Kostiantynivka, mostly in the form of infiltrations rather than firm control; its most recent assessment suggests it has spread to most of the city ; but overall Russian forces have been slowing down — capturing 16.6 sq km/day in H1 2025 vs. just 1 km/day in June 2026, and in July ISW assessed Russia was actually losing territory at 1.6 sq km/day (https://www.aljazeera.com/features/2026/7/31/russia-appears-to-infiltrate-first-fortress-city-as-ukraine-changes-guard). - [2026-06-10] An outside analyst (RCSGS) framed Kostiantynivka as the precondition for, not equivalent to, taking the wider fortress belt, noting the fall of Kostiantynivka demonstrates Russia can still penetrate heavily fortified urban defences given sufficient time and casualties... but it does so slowly, at a cost... The capture of the southern anchor advances the timeline; it does not compress it into the weeks that maximalist commentary implies (https://www.rcsgs.org/publications/blog/battle-for-kostiantynivka-and-the-donbas-fortress-belt). - [2026-06-10] Earlier in the battle, ISW estimated Russian control at roughly 5% in late 2025, rising to ~12.69% by June 2026 and "presence" (infiltration, not control) in 37% by early July 2026 — illustrating that "presence" and confirmed "control" (the relevant threshold for this market) diverge significantly and progress on confirmed control has been incremental over many months. - Base-rate pattern across comparable fortress-belt/urban sieges (Avdiivka: ~4 months; Pokrovsk/Myrnohrad: ~21-22 months from frontal assault to full capture) suggests full, ISW-confirmed capture of a contested medium city historically takes many months to roughly two years once heavy urban fighting begins, and claimed captures by Russian officials have repeatedly preceded actual ISW-confirmed control by weeks-to-months or turned out to be false/premature (as with the July 2026 Kostiantynivka claim itself). BOTTOM LINE: Historically, Russian claims of "full capture" of Donbas fortress cities (Avdiivka, Pokrovsk) have preceded ISW/DeepState confirmation by weeks to months, and comparable sieges of fortified cities have taken 4-22 months from heavy urban engagement to confirmed full control; Kostiantynivka has already seen a premature July 2026 "capture" claim rejected by ISW, and as of late July 2026 Russian advances there were reportedly slowing/reversing, so the outside-view base rate favors continued contestation rather than full, ISW-confirmed capture within the remaining ~3 months to the Dec 31, 2026 deadline, though it is not impossible given the city's weakened defenses. NOT FOUND: A precise, dated ISW map percentage for Kostiantynivka control as of September 2026 (most recent figures found are from late July 2026); any formal betting-market or expert numerical probability estimate specific to this contract; confirmation of a current ceasefire/negotiation status that could trigger the "negotiated settlement" clause.

YES means: the ISW map (or DeepStateMap/credible reporting per the fallback clause) shows the entirety of Kostyantynivka shaded under "Assessed Russian-Controlled Terrain" or "Assessed Russian Advances" continuously through a full update cycle, or Russia obtains actual control via a negotiated settlement, before December 31, 2026. - [2026-09-07] Russia's offensive effort near Kostyantynivka is officially still rated as a "subordinate main effort," with Russian forces simultaneously pushing on the city from the south/southwest and trying to envelop the wider fortress belt via Lyman/Dobropillya, showing the attack has not stalled out entirely but remains incremental and multi-pronged rather than a single collapsing front. (https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-12-2026) - [2026-09-25/26] ISW's dated assessment states Russian forces "recently advanced in western Kostyantynivka," with geolocated footage of a Ukrainian airstrike on a Russian position there indicating no remaining Ukrainian positions in that sector — a concrete, named-sector gain rather than vague "presence." Russian forces recently advanced in western Kostyantynivka. Ukrainian forces conducted an airstrike on a Russian position in western Kostyantynivka, according to geolocated footage published on September 25, indicating that there are likely no Ukrainian positions in the area. (https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-26-2026) - [2026-09-11] An independent tracker (Russia Matters, synthesizing DeepState data) confirms the broad trend favors continued Russian gains: in the week of Sept 1–8, 2026, Russian forces saw a net gain of 20 square miles of Ukrainian territory , with DeepState specifically flagging Russian advances "near Kostyantynivka and Chervonyi" on Sept 5 and Sept 9 (https://www.russiamatters.org/news/russia-review/russia-review-sept-4-11-2026). - [2026-09-16] The same tracker's four-week roundup (Aug 17–Sept 14) lists Kostyantynivka among eleven settlements near which Russian forces made a net gain of 58 square miles of Ukraine's territory (the equivalent of about 2.5 Manhattan Islands) in the past four weeks , indicating the city remains an active locus of confirmed (not just claimed) Russian advance by an independent Ukrainian OSINT source (https://www.russiamatters.org/news/russia-ukraine-war-report-card/russia-ukraine-war-report-card-sept-16-2026). - [2026-09-27] A battle-tracking analyst (Nordexium) reporting on Ukraine's General Staff data notes sustained, high-volume pressure: Ukraine's General Staff reported 25 Russian assaults around Mykolaipillia, Kostiantynivka, Novoselivka, Illinivka, Dovha Balka and Rusyn Yar in a single day, with a Russian correspondent separately claiming efforts to outflank Oleksiievo-Druzhkivka, showing Russia is still actively expanding the operation's geographic scope beyond the city itself (https://nordexium.substack.com/p/kostiantynivka-russian-forces-maintain). - [2026-09-05/early-Sept] Russia Matters' review frames the Kremlin's own target date as matching this market's window: Putin has set at least 15 deadlines for taking the region since February 2022, and Russian forces have not captured Kostyantynivka after 11 months of fighting... making the Kremlin's December 31 deadline highly unrealistic — notably, Russia's own command still treats Dec 31, 2026 as its internal objective, meaning a determined push timed exactly within this market's resolution window is a named Russian institutional goal, not just analyst speculation (https://www.russiamatters.org/news/russia-review/russia-review-sept-4-11-2026). - [2026-01-05] A Ukrainian-sourced operational report (CDS Daily Brief) describes the Russian operational plan in granular terms as a coordinated "double envelopment" of the whole Druzhkivka–Kostyantynivka agglomeration using multiple combined-arms armies (3rd, 8th, 51st) plus an Army Corps, suggesting Russia has committed large multi-army forces specifically to close the pincers around the city rather than relying on a single stalled axis. the enemy plan envisages a double envelopment of the entire Druzhkivka–Kostyantynivka agglomeration in two stages... the command of the enemy "Yug (South)" Operational Grouping delivers the main strike... To seize Kostyantynivka, the enemy has concentrated formations and units simultaneously from the 3rd, 8th, and 51st Combined Arms Armies, the 3rd Army Corps, and the 78th Motorized Rifle Regiment (https://cdsdailybrief.substack.com/p/russias-war-on-ukraine-050126). - [2026-07-29] ISW itself, prior to the premature July capture claim, characterized the city's trajectory as deteriorating even while contested: The situation in and near Kostyantynivka is deteriorating, but Russian forces have not seized the city despite Russian claims. Fighting will likely continue for several weeks as Russian forces try to consolidate the positions they have gained through infiltrations — establishing that ISW's own baseline narrative is one of gradual consolidation, which is the exact mechanism (not a sudden collapse) that would most plausibly produce a "Yes" by year-end if it continues at the current rate for three more months. - [2026-09-29] Mechanism for YES: continued Russian glide-bomb-enabled infiltration (confirmed by ISW's July 29 point on aviation advantage) combined with the newly-confirmed western Kostyantynivka clearance (Sept 25-26) and sustained high-tempo assaults (25+/day per General Staff) suggests Russia needs only a few more months of similar incremental consolidation — not a battlefield breakthrough — to fully shade the remaining contested core and eastern districts, especially if Ukrainian logistics via Druzhkivka are further degraded as the "Yug" pincer plan intends. BOTTOM LINE: The strongest case for YES rests on documented, dated, multi-source confirmation (ISW Sept 26, DeepState/Russia Matters Sept 11–16) that Russia is still making incremental but real, confirmed advances inside Kostyantynivka (not just claims) using a large committed multi-army force executing an explicit envelopment plan, with Russia's own command reportedly targeting a December 31, 2026 deadline that aligns with this market's resolution date — meaning if the current slow-but-steady consolidation pace persists uninterrupted for three more months, full shading becomes plausible, particularly via the western-district gains already confirmed in late September. NOT FOUND: A current (October 2026) DeepStateMap percentage-of-control figure for Kostyantynivka specifically; any confirmed Russian mechanized breakthrough or encirclement completion (versus infiltration) in the past 30 days; any negotiated-settlement text addressing Kostyantynivka's status.

YES means: Russia achieves ISW-mapped (or DeepStateMap-confirmed, or negotiated-settlement) control of the entirety of Kostyantynivka's municipal boundary, with that shading persisting through a full ISW update cycle, by December 31, 2026, 11:59 PM ET. - [2026-09-29] ISW's most current full assessment (data cutoff 1:30 PM ET Sept 29) makes no claim of Kostyantynivka capture; its "Key Takeaways" that day center on Operation Vivaldi near Lyman, Russian defense-spending plans, and Duma elections — Kostyantynivka registers only as one of four "subordinate main efforts" still in progress, not a resolved objective. https://www.criticalthreats.org/analysis/russian-offensive-campaign-assessment-september-29-2026-6abc6f16de2f1 - [2026-09-26] ISW's own Sept 26 report frames the broader war narrative around Ukrainian counteroffensive success (Operation Vivaldi recapturing Lyman-area settlements) and Putin reportedly "rethinking his theory of victory," noting Russian forces have achieved near-zero net gains since March 2026, however, while Ukrainian forces have conducted successful counterattacks in the Kupyansk, Oleksandrivka, and Lyman directions since late 2025 — the opposite momentum needed for a Dec 31 full capture. - [2026-09-26] On Kostyantynivka specifically, the same day's tactical section only records a single localized claim — Russian forces recently advanced in western Kostyantynivka — not a city-wide shift, consistent with months of inch-by-inch, not wholesale, change. - [2026-09-20] Just nine days before deadline-relevant reporting, ISW described Russian activity as merely an "infiltration mission," not a controlled advance: Russian forces recently conducted an infiltration mission in northwestern Kostyantynivka. Ukrainian forces struck a Russian-occupied building in northwestern Kostyantynivka during what ISW assesses was a Russian infiltration mission — the map-qualifying "Assessed Russian-Controlled Terrain"/"Advances" layers explicitly exclude "Infiltration Areas," a resolution-criteria technicality that keeps most contested ground as non-qualifying shading. - [2026-09-12] ISW's mid-September assessment shows Russian offensive energy diffusing toward Druzhkivka rather than consolidating Kostyantynivka itself: Russian forces continued offensive operations in the Kostyantynivka-Druzhkivka direction on September 11 and 12 but did not advance. Russian milbloggers claimed on September 12 that Russian forces are attempting to advance towards Druzhkivka from Raiske — a shift of main effort away from finishing Kostyantynivka reduces the odds of full capture by year-end. - [2026-10-01] Ukraine's General Staff's Oct 1 daily update (covering Sept 30) still lists Kostyantynivka among active but unresolved contact points — The invaders carried out assault operations in the areas of Oleksiyevo-Druzhkivka, Kostyantynivka, Novoselivka, Dovha Balka, Mykolaypillya, and Petrivka — language of ongoing "assault operations," not capture, one day before this report's cutoff. - [2026-07] (context, not new) A third-party mapper comparison showed wide divergence in assessed control (DeepState <1%, independent analyst ~40%, Russian "Divgen" source ~73%), illustrating that even pro-Russian sources were not claiming full capture as of that snapshot, underscoring how far any tracker is from the "entirety" threshold this market requires. https://x.com/AMK_Mapping_/status/2069052703263854856 - [2026-07] Base-rate mechanism: Wikipedia's battle tracker still labels the engagement "Ongoing" with no resolution date, and a Ukrainian brigade general (June 2026) called claims of any Russian-held territory in the city "premature and an exaggeration" — the same discipline ISW has since applied to every subsequent Russian capture claim. https://www.pravda.com.ua/eng/news/2026/06/16/8039670/ - Resolution-criteria technicality: the market requires qualifying shading to "persist through the next full ISW daily update cycle," and ISW has repeatedly flagged Russian MoD claims (including Kostyantynivka in July) as premature information operations later walked back in subsequent updates — any one-day "full capture" headline is structurally insufficient without multi-day persistence, which has not yet happened even once for this city. - Status-quo inertia: with only three months remaining (Oct 1–Dec 31) and the front line inside the city having moved only incrementally (western Kostyantynivka infiltration-to-advance in late September) after nearly a full year of fighting since October 2025 infiltration began, the trend rate implies the "last mile" of urban clearance — historically the slowest phase in Fortress Belt sieges — is very unlikely to complete within this narrow window absent a negotiated settlement. BOTTOM LINE: Every available primary-source ISW update through September 29, 2026, plus the October 1 Ukrainian General Staff report, shows Kostyantynivka still contested with only incremental, localized Russian gains (western/northwestern sectors) and no citywide qualifying shading, while Russian offensive weight is visibly diffusing toward Druzhkivka and Ukraine has regained initiative elsewhere (Operation Vivaldi); this status-quo trajectory and the market's strict persistence/layer-exclusion rules favor a NO resolution absent a sudden battlefield collapse or negotiated settlement in Q4 2026. NOT FOUND: Any ISW or DeepState control-percentage figure specific to Kostyantynivka dated after early July 2026 (ISW has stopped publishing a single percentage figure in recent reports); confirmation of negotiated-settlement terms addressing Kostyantynivka specifically; a DeepStateMap snapshot from September 2026.