On February 24, 2022, the border towns of northern Ukraine were among the first to face the Russian invasion. In Sumy, residents joined forces with the Territorial Defense, organizing resistance and blocking the advance of Russian troops.

Trostyanets, one of the cities most affected in the region, remained under occupation for 31 days. Despite the violence, residents risked their lives to share information with the Defence Forces of Ukraine, organized evacuations, and provided food and medical aid.

In April 2022, Russian forces were pushed out of the Sumy region.

In recognition of the courage and resilience of their residents, Sumy and Trostyanets were awarded the honorary title of Hero City of Ukraine in 2025.

The postal block “Hero Cities — Sumy Region” features the K3 building of Sumy State University and the historic Round Yard in Trostyanets.

The issue was released on March 12, 2026.

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