Two separate groups, the Dakota Land Company of St. Paul and the Western Town Company of Dubuque, Iowa organized in 1856 to claim the land around the falls, considered a promising townsite for its beauty and water power. Each laid out claims, but worked together for mutual protection. They built a temporary barricade of turf which they dubbed "Fort Sod", in response to native tribes attempting to defend their land from the settlers. Seventeen men then spent "the first winter" in Sioux Falls. The following year the population grew to near 40.