Perham Township is a township in Otter Tail County, Minnesota, United States. The population was 931 at the 2000 census. Perham Township was originally called Marion Lake Township for the lake in its southwest corner, and under the latter name was organized in 1872. The present name was adopted in 1877 to match that of the village of Perham loc…Perham Township is a township in Otter Tail County, Minnesota, United States. The population was 931 at the 2000 census. Perham Township was originally called Marion Lake Township for the lake in its southwest corner, and under the latter name was organized in 1872. The present name was adopted in 1877 to match that of the village of Perham located therein.