The Siennica Commune, located in the Masovian Voivodeship within the Mińsk County, was established on January 1, 1973. Its administrative seat is in the town of Siennica. The commune covers an area of 110.73 km², of which 77% is agricultural land and 15% is forested. In 2014, it was home to 7,338 residents. During the period of the Kingdom of Poland, the commune belonged to the Mińsk County in the Warsaw Governorate, and it incorporated the town of Siennica, which had been stripped of its town rights. From 1975 to 1998, the commune operated within the Siedlce Voivodeship. The local government is led by a team headed by Mayor Stanisław Duszczyk, with Deputy Mayor Mariusz Kozera and Secretary Ksenia Wąsowska. Among the villages within the commune are Bestwiny, Boża Wola, and Krzywica, while Wiśniówka is a locality without village status. The Siennica Commune constitutes 9.51% of the area of Mińsk County. An interesting fact is the diversity of the age structure of its inhabitants, as observed in the 2014 population pyramid. The commune borders the communes of Cegłów, Kołbiel, Latowicz, Mińsk Mazowiecki, Parysów, and Pilawa, which creates opportunities for regional cooperation.