Coeur d'Alene's Old Mission State Park is a heritage-oriented state park in northern Idaho in the western United States, preserving the Mission of the Sacred Heart, or Cataldo Mission, a national historic landmark. The park contains the church itself, the parish house, and the surrounding property. Built in 1850–1853, Mission of the Sacred Heart is the oldest standing building in Idaho. It was designated a National Historic Landmark in 1961, and put on the National Register of Historic Places in 1966.