The gmina covers an area of 111 square kilometres (42.9 sq mi), and as of 2006 its total population is 6,912 (7,334 in 2013).

The responsible German soldiers proclaimed to the gathered population that the Poles "pigs".

When some of the people tried to fulfil their physiological needs the German soldiers humiliated them and told that those who want can go outside the church.

During the murder other German soldiers used incendiary grenades to burn down 70 buildings.

[2] Gmina Siennica contains the villages and settlements of Bestwiny, Borówek, Boża Wola, Budy Łękawickie, Chełst, Dąbrowa, Dłużew, Drożdżówka, Dzielnik, Gągolina, Grzebowilk, Julianów, Kąty, Kośminy, Krzywica, Kulki, Lasomin, Łękawica, Majdan, Nowa Pogorzel, Nowe Zalesie, Nowodwór, Nowodzielnik, Nowy Starogród, Nowy Zglechów, Pogorzel, Ptaki, Siennica, Siodło, Stara Wieś, Starogród, Strugi Krzywickie, Świętochy, Swoboda, Wojciechówka, Wólka Dłużewska, Żaków, Żakówek, Zalesie and Zglechów.