A pretty big hunk of rock with some incredible routes. Like most of the Rushmore area, it is a bit confusing at first. After you've located a couple routes things get much easier. Some fun, popular moderates include Solo System, Star Dancer, and Weird Water.
The Marker area is one of the closest to the monument and just off 244. Coming from in from the monument, look for the 2nd? pullout on the left. If you get the correct one, the trail and signin board are right across the street.
Before you start going, look up and to the right - the beautiful summits are the Middle & Inner Markers. Follow the trail straight in and up the gully, the Middle Marker is on the right, the Inner Marker is behind it.