Independence Rock is a large granite rock, approximately feet ( m) high, in southwestern Natrona County in the U.S. state of Wyoming, along Wyoming Highway 220. During the middle of the 19th century, the rock was a prominent and well-known landmark on the Oregon, Mormon and California emigrant trails. It was designated a National Historic Landmark on January 20, 1961. It is now part of Independence Rock State Historic Site, owned and operated by the state of Wyoming.