In the spring, a thundering torrent of muddy brown water plunges 185 feet into the canyon of the Little Colorado River about 30 miles northeast of Flagstaff. The best time to see the spectacle is during March and April; in other months the river may dry up and yield nothing but an unimpressive trickle. High-clearance vehicles will be required for the dirt access roads, which should be avoided if muddy.
A lava flow from Merriam Crater, the large cinder cone 10 miles southwest, created the falls about 100,000 years ago. The tongue of lava filled the canyon, forcing the river out of its gorge, around the dam, and back over the rim into the original channel.
Grand Falls lies on the southwest corner of the Navajo Indian Reservation. From Flagstaff, take US 89 north 1.8 miles past Flagstaff Mall, turn right eight miles on the Camp Townsend-Winona Road, then turn left onto Leupp Road. Follow Leupp Road northeast 13 miles, then turn north 10 miles on unpaved Indian Route 70 or turn north 10 miles on unpaved Indian Route 6910 between Mileposts 5 and 6, seven miles farther east; the overlook is on a rocky road a half mile west of the main road. (If you come to the Little Colorado River ford, you've gone 0.4 mile too far.) The AAA Indian Country map will help in navigation, as the unpaved roads may not be signed. You'll see hues of the Painted Desert as the road descends to the river.
Other approaches: I-40 Winona Exit 211 (14 miles east of Flagstaff)—drive two miles on the Townsend-Winona Road, then turn right on Leupp Road to the Grand Falls turnoffs; I-40 Exit 245 (46 miles east of Flagstaff)—take AZ 99 to Leupp, then Leupp Road to the Grand Falls turnoffs. From Kykotsmovi, on the Hopi Indian Reservation, take paved Indian Route 2 southwest 49 miles to Leupp, then Leupp Road to the Grand Falls turnoffs.
The overlook has picnic tables; admission is free, though the Navajo Tribe asks you to help keep the area clean and leash your dogs so they won't disturb livestock. Also, don't go out in the streambed—mud makes the rocks very slippery and the strong currents have carried people over the falls to their deaths.
On to Meteor Crater