The trail can be used in either direction, but this description is for the recommended counterclockwise loop:
Leaving the Bar-M Loop
at the Circle-O's southern trailhead, run 1/4 mile on dirt doubletrack to the berm bowl at the junction with the Rockin' A
trail. This is where the real fun begins.
Head left (NE) from the berm bowl to follow the Circle-O trail. The path is marked by a rust-colored line painted on the Entrada sandstone. Follow this line for nearly 3 miles as it winds through tight turns, over quick dips, and down short drops. Along the way, you'll reach the border of Arches National Park before climbing back to the Circle-O's northern junction with the Bar-M Loop