Dividing the Front: Regional Dynamics and Force Concentrations in Ukraine, 2025

In 2025 the Russo-Ukrainian front line spans over 1,000 kilometres, from the Kupiansk forests in the northeast to the Dnipro River delta in the south. While the war retains a uniform character of attrition and drone-saturated trench fighting, the regional dynamics, force concentrations, and operational goals vary significantly across the theatre. This article maps out the key zones of combat, explores the evolving structure of Russian and Ukrainian forces, and presents a theater-wide analysis of deployments and tactics.

Overview of Frontline Geography

The front line is divided into several operational sectors:

• Northeast Axis (Kharkiv Oblast – Kupiansk to Svatove)

  
  

• East-Central Axis (Luhansk–Donetsk – Kreminna to Pokrovsk / Avdiivka)

  
  

• South-Central Axis (Zaporizhzhia – Velyka Novosilka to Robotyne)

  
  

• Southern Axis (Kherson Oblast – Dnipro River line)

Each of these fronts differs in terrain, force posture, and operational tempo, shaping the deployment and function of Ukrainian and Russian units.

Russian Force Concentrations (2025)

Estimated Theatre-Wide Russian Troop Presence: ~450,000–500,000

Frontline Combat Forces: ~200,000–250,000

Key Features

• Rotational depth: Russia rotates units between front and rear echelons, often using penal (so-called "Storm-Z") units as expendable assault troops.

  
  

• Corps Structure Revived: Once thought consigned to history as too bulky and clumsy, the Russian military has reintroduced operational-level corps commands in Luhansk and Zaporizhzhia each with two or more divisions any anywhere between 40,000 and 80,000 troops under single command.

  
  

• Heavy force concentration around Bakhmut, Avdiivka, and Kupiansk axes.

By Region

• Kupiansk–Svatove (Northeast Front):

  
  

  • 6th Combined Arms Army, 1st Guards Tank Army (remnants), elements of airborne VDV (elite Russian Airborne) forces

    
    

  • Objective: Draw Ukrainian reserves northward and threaten a breakthrough toward Kharkiv.

    
    

  • Strength: ~50,000–60,000 troops

  
  

• Donetsk Axis (Bakhmut–Avdiivka):

  
  

  • 2nd Army Corps (LPR forces), 150th Motor Rifle Division, Chechen units, and Storm-Z detachments

    
    

  • Russia’s most active offensive axis, with daily infantry assaults, particularly near Chasiv Yar and Pokrovsk.

    
    

  • Strength: ~60,000–70,000 troops

  
  

• Zaporizhzhia Front (Robotyne–Verbove):

  
  

  • Elements of 58th Combined Arms Army, 3rd Army Corps, Vostok Brigade, and 76th VDV (Russian Airborne Forces) Division

    
    

  • Entrenched defence posture using layered minefields, anti-tank zones, and drone overwatch

    
    

  • Strength: ~40,000–50,000 troops

  
  

• Kherson–Dnipro River Line:

  
  

  • Defensive force posture, focused on artillery duels and interdiction

    
    

  • Includes naval infantry units and local Rosgvardiya (Russia's National Guard - troops intended to suppress internal emergencies) garrisons

    
    

  • Strength: ~25,000–30,000 troops

  
  

Ukrainian Force Concentrations (2025)

Estimated Active Frontline Forces: ~130,000–150,000

Total Mobilised Personnel: ~600,000–700,000 (includes logistics, reserves and training)

Key Features

• Brigade-based structure (typically 1,000 to 5,000 troops) with independent command in the NATO style, and Western-style combined arms integration (e.g. ensuring shells and bullets are compatible across different weapons)

  
  

• Elite Mechanised and Assault Brigades (3rd Assault, 47th Mechanised, 82nd Air Assault) often held in reserve or used for counterattack roles

  
  

• Reliance on reserves and rotation due to manpower fatigue

By Region

• Kupiansk–Svatove Axis:

  
  

  • 57th Motorised Brigade, elements of 92nd Mechanised, Territorial Defence (reservist) units

    
    

  • Defensive posture with fallback lines and heavily fortified towns

    
    

  • Strength: ~25,000–30,000 troops

  
  

• Bakhmut–Avdiivka Axis:

  
  

  • 5th Assault, 3rd Assault, 24th Mechanised and 93rd Mechanised Brigades

    
    

  • Urban combat experts; heavy use of drones, snipers, and anti-armor ambushes

    
    

  • Strength: ~35,000–40,000 troops

  
  

• Zaporizhzhia Front (Orikhiv–Robotyne):

  
  

  • 47th Mechanised Brigade, 82nd Air Assault, 46th Airmobile, 116th Mechanised

    
    

  • Use of Bradleys, Leopards, and mine-clearing equipment; focus on small-scale raids

    
    

  • Strength: ~30,000–35,000 troops

  
  

• Dnipro River (Kherson sector):

  
  

  • Marine Infantry units (35th, 36th), Special Forces elements

    
    

  • Conduct amphibious operations, drone raids, and reconnaissance

    
    

  • Strength: ~15,000–20,000 troops

  
  

Ukrainian Order of Battle (ORBAT) Snapshot (2025)

Unit	Type	Deployment Zone	Notable Equipment
3rd Assault Brigade	Assault	Chasiv Yar	FPV drones, Western optics
47th Mechanized	Mech	Zaporizhzhia	M2 Bradleys, Leopard 2A6
82nd Air Assault	Air Assault	Zaporizhzhia Reserve	Challenger 2, Stryker
5th Assault	Assault	Avdiivka / Pokrovsk	Urban CQB (close quarters battle) specialists
36th Marine Brigade	Marines	Kherson	Amphibious drone raiding
92nd Mechanized	Mech	Kupiansk	Mi-8 heliborne raids, ATGMs

Russian Order of Battle (ORBAT) Snapshot (2025)

76th VDV Division	Airborne	Zaporizhzhia	Elite mobile reserve
150th Motor Rifle Div.	Mech Infantry	Avdiivka	Russian shock infantry
6th Combined Arms Army	Multirole	Kupiansk	Heavy armour, EW support
Chechen “Akhmat” Units	Light Infantry	Bakhmut	Urban clearing and propaganda roles
58th Combined Arms Army	Multirole	Tokmak–Robotyne	Layered defences
Naval Infantry	Marines	Kherson	Defence of river crossings

Logistics, Rotation, and Strategic Depth

• Russia operates from a deep logistical base stretching from Rostov-on-Don to Belgorod. Frontline units receive replenishment via railheads and road convoys, though partisan activity and long-range Ukrainian strikes have forced decentralisation.

  
  

• Ukraine depends heavily on Western logistical chains, running through Poland and Romania. Artillery shells, spare parts and fuel are moved to forward positions under constant drone surveillance. The “last-mile” is increasingly done by drone or light electric vehicles to avoid detection.

  
  

• Unit Rotation:

  
  

  Ukraine now rotates brigades off the line every 3–4 months where possible. Russia performs rotations more haphazardly, with some units remaining understrength for extended periods due to attrition and lack of rotation to replace them.

  
  

  The result is uneven cohesion on both sides but better troop survivability for Ukraine.

Ukraine Frontline Overview (2025)

• Northern Front (Kharkiv Oblast):

  
  

  • Russian Forces: Concentrated around Kupiansk and Svatove, aiming to push westward.

    
    

  • Ukrainian Forces: Defensive lines established along the Oskil River, with fortified positions in Kupiansk.

  
  

• Eastern Front (Donetsk and Luhansk Oblasts):

  
  

  • Russian Forces: Heavy presence near Bakhmut, Avdiivka, and along the Siversk-Lyman axis.

    
    

  • Ukrainian Forces: Defensive strongholds in Chasiv Yar, Kramatorsk, and Slovyansk.

  
  

• Southern Front (Zaporizhzhia Oblast):

  
  

  • Russian Forces: Entrenched positions near Tokmak and Robotyne.

    
    

  • Ukrainian Forces: Offensive operations targeting Melitopol corridor.

  
  

• Southern Front (Kherson Oblast):

  
  

  • Russian Forces: Defensive posture along the Dnipro River’s left bank.

    
    

  • Ukrainian Forces: Control of the right bank, with cross-river operations ongoing.

  
  

Operational Highlights by Region

• Kharkiv Oblast: Ukrainian forces have fortified positions along the Oskil River to prevent Russian advances toward Kharkiv city. Russian units are attempting to establish bridgeheads west of the river.

  
  

• Donetsk Oblast: The battle for Bakhmut continues with intense urban combat. Ukrainian assault brigades are engaging Russian motor rifle divisions and Chechen units in close-quarters battles.

  
  

• Zaporizhzhia Oblast: Ukrainian mechanized and air assault brigades are conducting offensive operations aimed at breaking through Russian defensive lines near Tokmak, with the goal of reaching Melitopol.

  
  

• Kherson Oblast: Ukrainian marine brigades are executing cross-river operations to disrupt Russian supply lines and establish footholds on the left bank of the Dnipro River.

Outlook for 2025

The strategic situation in 2025 reflects tactical stalemate with regional fluidity. Russia seeks incremental gains in Donbas, while Ukraine prioritises long-range interdiction and small-unit penetration. Neither side has the force mass or tactical edge to mount a deep breakthrough—yet. The decisive variable may not be the brigade on the front line, but the factory and logistics chain behind it.