Register Cliff is a sandstone cliff and featured key navigational landmark prominently listed in the 19th century guidebooks about the Oregon Trail, and a place where many emigrants chiseled the names of their families on the soft stones of the cliff —it was one of the key checkpoint landmarks for parties heading west along the Platte River valley west of Fort John, Wyoming which allowed travelers to verify they were on the correct path up to South Pass and not moving into impassable mountain terrains—geographically, it is on the eastern ascent of the Continental divide leading upward out of the great plains in the east of the U.S. state of Wyoming. It is notable as a historic landmark for 'registering' hundreds of emigrants on the Oregon Trail (thus also the other northern Emigrant Trails