On February 24, 2022, the border towns of northern Ukraine were among the first targets of the Russian invasion.

The residents of Sumy, together with the Territorial Defense Forces, organized active resistance:

thousands of volunteers, armed with weapons, blocked the approaches to the city and held back the advance of Russian columns.

Trostenets, one of the cities in the Sumy region most affected by the hostilities, was under occupation for 31 days. Despite the atrocities committed by the invaders, the townspeople risked their lives to pass on important information to the Armed Forces of Ukraine, organize evacuations, and provide people with medicine and food.

In April 2022, Russian troops were forced to leave the Sumy region.

In order to commemorate the feat, mass heroism, and resilience of citizens in defending their cities during the repulsion of the Russian Federation's armed aggression, the President of Ukraine awarded Sumy and Trostianets the honorary title of “Hero City of Ukraine” in 2025.

The postage stamp block “Cities of Heroes. Sumy Region” depicts the K3 building of Sumy State University (Sumy) and the “Round Yard” (Trostianets).