Terrace Hill, also known as Hubbell Mansion, Benjamin F. Allen House, and Iowa Governor's Mansion, is the official residence of the Governor of Iowa. Located at 2300 Grand Avenue in Des Moines, Iowa, it is an example of Second Empire architecture. The home measures 18,000 square feet . It sits on a hill overlooking downtown Des Moines, and has a 90-foot (27 m) tower that offers a commanding view of the city. The house was designated a National Historic Landmark in 2003.