The Cordenio Severance House is a mansion in Cottage Grove, Minnesota, United States, built for attorney Cordenio Severance (1862–1925). The mansion, also known as Cedarhurst, was first built as a simple country farm house shortly after the American Civil War. It was expanded in 1886 to serve as the summer residence of the Severance family. Between 1911 and 1917, additions designed by architect Cass Gilbert expanded the house into a mansion with 12,000 square feet (1,100 m2) and 26 rooms. The Cordenio Severance House was listed on the National Register of Historic Places in 1976 for its local significance in the themes of architecture and law. It was nominated for its association with Cordenio Severance, a leading attorney in Saint Paul, Minnesota, from 1887 to the 1920s, and for being an