The Mines of Spain State Recreation Area and E. B. Lyons Nature Center is a state park in Dubuque County, Iowa, United States. It is near Dubuque, the eleventh-largest city in the state. The park features picnic areas, 15 miles of walking/hiking trails, 4 miles of ski trails, and the Betty Hauptli Bird and Butterfly Garden. It also includes archaeological sites of national importance as an early lead mining and smelting venture led by French explorer Julien Dubuque, as well as Dubuque's gravesite. These sites were collectively designated a National Historic Landmark District as Julien Dubuque's Mines.