Native Americans used the survey area for hunting and fishing and had permanent dwelling sites. Two Native American tribes were in constant conflict. The Dakota (Sioux) were being pushed from their home area by the Ojibwa (Chippewa) during the late 1700’s and early 1800’s. Burial mounds and artifacts can still be found. Some of the oldest remains of Native Americans were found near Pelican Rapids, Minnesota. The remains, nicknamed Minnesota Girl, were dated at about 11,000 B.C.
The first white men to enter the county were French and British fur traders. Efforts were made to set up trading posts on the Leaf Lakes and Otter Tail Lake. In the late 1800’s, most of the towns were built along the railroad lines. Lumber and agriculture were the major industries in the county at that time. The pine and hardwood forests, transportation system, and markets were instrumental in the development of Fergus Falls into a lumber center.
In 1870, the population of the county was about 2,000. At that time the principal languages spoken in the county were Norwegian, Swedish, German, and English (Mason, 1916). Otter Tail County was established in March 1858 by a legislative act. It was organized in 1868. The original county seat was Ottertail City.
The people of Fergus Falls organized a new county named Holcomb. In 1872, a legislative act abolished Holcomb County, added additional townships to the west, and established Fergus Falls as the county seat of Otter Tail County. There are 62 townships in the county. The county is named for the land formation where Otter Tail River enters Otter Tail Lake.