Łapy began as a gentry village in the 15th century. Fourteen separate villages in the area existed under the name Łapy in 1676, and these villages were all combined into one at the beginning of the 19th century. In 1795 Łapy was incorporated into the Austrian Partition of Poland, in 1807 into the Duchy of Warsaw, and in 1815 into the Russian Partition (Kingdom of Poland). In 1862 the town began to grow thanks to the development of a railway line that connected Warsaw and Petersburg and passed through the town. A rolling stock repair workshop was built in the town in 1870. Łapy became an officially urban settlement in 1903. The town expanded greatly during the interwar years, and it was granted town privileges in 1925.

From September 1939 until June 1941, Łapy was under Soviet occupation, and between 1941 and 1944 it was occupied by Germany. A ghetto was thus established between 1941 and 1942 that housed, in all, about 600 people, 450 of whom were transported to a temporary camp in Białystok. The town saw conspiracy activities by the Home Army, the Peasant’s Battalion, and the National Armed Forces-National Military Organization, which mainly carried out sabotage operations. Between 1944-1945 the town was the site of deportations of members of Polish independence organizations into the territory of the USSR by the People’s Commissariat for Internal Affairs (NKVD). The region once again saw resistance operations, this time in the form of anti-communist resistance activities.

Between 1956 and 1975 Łapy was a county capital.

This entry has been drawn up on the basis of material obtained from the PWN.