Foster County was established by the Territorial Legislature on January 4, 1873. The county was named to honor James F. Foster, the Commissioner of Immigration for Dakota Territory. It was originally a rectangular block of 42 townships. The county was not organized until the fall of 1883. Various townships were assigned to Griggs, Nelson, and Eddy Counties until at the present time Foster contains 18 townships. The county seat,and principal city, is Carrington, population 2267. A few early settlers arrived before the 1880's but many arrived after the origin of the county.