The commune of Kosów Lacki is located in the Mazowieckie Voivodeship, approximately 110 km north-east of Warsaw. Due to the proximity of the S8 expressway (from Warsaw to Białystok), with which the commune is connected by the high-standard Voivodeship road No 627, transport connections with the whole country and Europe are very good.
The commune is situated on the Bug River, and a part of its area belongs to the Bug River Landscape Park. The German Nazi death camp and the Treblinka labour camp (1941-1944) are located in the commune.
In Kosów Lacki large enterprises from the agri-food industry (District Dairy Cooperative in Kosów, Zakrzewscy Meat Processing Plant, Świderscy Meat Processing Plant, STAOIL Sp. z o.o. and general industry (Austenit Sztajerwald) as well as service companies (PHU MADO and PHU Elka) operate. There are also many small businesses, shops and service establishments operating in the commune, with mining (gravel) and agriculture playing an important role in the local economy.
The commune of Kosów Lacki is situated in the historical land of Southern Podlachia. As the geophysical division presents, the area of the commune is located mainly in the Siedlce Upland, and some parts of the commune - in such regions as the Bug River Gorge of Podlachia, Lower Bug River Valley, and the Wołomin Plain.