The Nels Severson Barn, also known as "Fort" Severson, is a historic barn located north of Carpenter in rural Mitchell County, Iowa, United States.

It is a two-story structure composed of irregularly-cut limestone with a gable roof.

Its large size and sturdy construction would protect the white settlers from Indian attacks.

[2] The barn was listed on the National Register of Historic Places in 1977.

This article about a property in Mitchell County, Iowa on the National Register of Historic Places is a stub.