As a result of the Partitions of Poland Łomża was annexed by Prussia in 1795. In 1807 it was included in the short-lived Polish Duchy of Warsaw, within which it was the seat of the Łomża Department. In 1815 Łomża became part of Congress Poland, which was forcibly integrated into the Russian Empire over the course of the 19th century. After the Russian massacres of Polish protesters in Warsaw in 1861, Polish demonstrations took place in Łomża, at which even romantic poet Władysław Syrokomla gave a public speech, however, they ended in October 1861 when the Russians imposed martial law. Afterwards the Polish resistance began preparations for an uprising. In 1863 the January Uprising broke out and many local Poles joined it. In July 1863, the Russians carried out a massacre of 50 unarmed young Poles in the nearby forest in Wygoda, mainly students of local schools, who joined the uprising. The victims were tortured and murdered in gruesome ways, some had their eyes gouged out, bones broken or insides torn out before they died. From November 1863, the Russians carried out mass arrests and confiscations of Polish property, and many insurgents escaped from the country. Russians deported hundreds of Poles from the county to Katorga to Siberia, and Łomża was one of the sites of Russian executions of Polish insurgents. At the place of the executions, Poles put up crosses several times, and the Russians removed them.