Map Rock Petroglyphs Historic District in Canyon County, Idaho, centers on a large basalt boulder bearing petroglyphs believed to have been created by Northern Shoshone people before westward expansion reached Idaho in the 19th century. Robert Limbert named the stone Map Rock in the early 1920s because he thought its carvings depicted the Snake River valley; later writers suggested that, if so, it might be among the world’s oldest maps. The boulder narrowly escaped removal or dismemberment for display in 1924, though it was damaged. In 2012, Canyon County acquired Map Rock and 38 surrounding acres, helping preserve this notable archaeological setting.