Sitting near the Horseshoe bend. The Colorado river flows from Colorado to Utah and enters Arizona at Page where it forms a narrow Canyon called Glen Canyon. Just upstream a mile or two, is the Glen Canyon Dam which stops the water and forms Lake Powell. The canyon is made up for Navajo sandstone which stretches across a lot of states in Western United States.
The Horseshoe Bend is near the city of Page at the northern border of Arizona and is not part of any National park or National preserve or monument. The place is unmanned and has no entry gate or fee. There is a parking lot, from where one needs to walk a 3/4 mile to reach the corner of the canyon.
If you are driving from Utah, take 89S and drive a mile or two after crossing the city of Page. Keep looking on the right for a board mentioning Horseshoe Bend.
If driving from Flagstaff, take 89N and check with local traffic whether 89N is open till Horseshoe Bend. In case the road is closed, you need to take a detour at 89T after a few miles after the turn at Yuba City. Keep driving till you meet US 98 and take West on 98W till you meet US 89 where you need to go South on 89S.