Chortkiv offensive

The Chortkiv offensive (Ukrainian: Чортківська офензива, Чортків, Polish: Czortkowska ofensywa, Czortków; 7–28 June 1919) also known as June offensive was one of the most successful counteroffensive military operations of the Ukrainian Galician Army (UHA) against the Polish Army during the Polish-Ukrainian War in 1918–1919. Around 19,000–20,000 Ukrainians pushed back the Poles along the entire front of the 39,000-strong Polish Army, reinforced by the French Third Republic.

Goals
The Ukrainian goal of the offensive was to push the Polish Army back to the Zolota Lypa River in order to improve the morale among the soldiers of the Ukrainian Galician Army and locals to mobilize a larger force and push the Poles back past Lviv, Peremyshl, Kholm, Lublin and other territories claimed by the West Ukrainian People's Republic after 1 November 1918.

Ukrainian offensive
On 8 June 1919, the Ukrainian Galician Army numbering around 19,000–20,000 men assaulted Chortkiv, forcing the Poles to retreat to the Holohory–Peremyshliany–Bukachivtsi line. Under the command of general Oleksandr Hrekiv, the Ukrainian forces came close to Lviv, the main city of the province, and were close to taking it from the Polish forces, which was their greatest success.

The Ukrainian forces also gained victories at Yahilnytsia (7–8 June), Vyhnanka (8 June), Bilobozhnytsia (9–10 June), Kopychyntsi (10 June), Yazlovets (11–12 June), Buchach (12 June), Terebovlya (12–13 June), Monastyryska (13 June), Ternopil (14 June), Kozova (14 June), Nyzhniv (14–15 June), Pidhaytsi (15–16 June), Berezhany (20–21 June). The battle near Berezhany didnt achieve a success and despite the capture Polish forces repulsed the offensive. On June 23rd Polish forces attacked Holohory the well-executed operation ended with the Ukrainians being pushed back beyond the Zlota Lipa River.

Polish counterattack
As the Ukrainian Galician Army suffered from a lack of ammunition, on 28 June better equipped and much larger Polish forces broke through the Ukrainian lines at Janczyn and forced them to retreat and evacuate across the Zbruch River. Due to the support of the French Third Republic in the war, the Polish Army was able to assemble a much larger and more powerful force of around 39,000–40,000 men against the Ukrainian Galician Army, and the Ukrainians were forced to return to their previous positions and abandon the cities and villages they had captured during their recent offensive. Eventually the Ukrainian forces were forced back toward the Dnipro Valley which then was controlled by the Ukrainian People's Republic, another nascent Ukrainian State.

Aftermath
The breakthrough at the Ukrainian front on Janczyn forced the Ukrainians to evacutae, this meant the end for the Chortkiv offenisve, and on July 16, 1919, the ZUNR government moves to the territory of Dnieper Ukraine. Carried out by small forces against the overwhelming forces of the enemy due to the shortage of ammunition and the absence of strategic reserves, the Chortkiv offensive despite initial victories could not achieve its success.