 The province was made up of 9 powiats (counties), and had 12 substantial towns or cities.In 1921, the population of the province numbered 879,417, with the population density of about 20.8 persons per km², the lowest in interwar Poland.By 1931, thanks to a government-sponsored settlement programme and the progressive development of education, commerce and industry in the urban centres (neglected under the Tsarist Russia), the population had risen to 1,132,200, and the population density to 31 per km².