The Otter Tail County Historical Society is a local history museum and research library and archives in Fergus Falls, Minnesota. It is dedicated to preserving the history of the entire county. It was located in the county courthouse from 1927 until 1972 when funds were raised to build a new museum. In 1982, an agricultural wing was added. The museum offers permanent exhibits which explore Native American history, wildlife, and life during the 1910s. Temporary exhibits are also on display.