The San Francisco Volcanic Fields have some 600 plus remnants of tectonic activity visible today throughout the Flagstaff area. Mount Humphreys and Sunset Crater may represent some of the more famous examples, but volcanic lava flows are also responsible for some of the lesser known geologic features such as Keyhole Sink.
This particular feature acts as a giant catchments basin funneling snowmelt or rainfall into dammed box canyon. This has served as a reliable water source for wildlife and ancients across the millennia. Consequently this has served another purpose as a reliable ambush site for four-legged and two-legged predators alike.
The Sinagua people have left examples of their architecture (see Elden Pueblo Ruins, Williams Clover Site Ruins or Walnut Canyon Ruins) as well as their rock art (see V-Bar-V, Honanki Ruins, or Wupatki Crack-In-Rock Ruins) throughout the San Francisco Volcanic Fields. These ancient people are thought to have left their marks in the basalt cliffs of Keyhole Sink. They have depicted deer entering the box canyon and the subsequent successful hunt. These rock art depictions are visible today on the rock art panels located in Keyhole Sink.
As you travel along Route 66 towards the TH parking, you will notice Sitgreaves Mountain
to the north across some open prairie. Although Sitgreaves' 1851 expedition and Beale's 1857 expedition passed within sight of the Keyhole Sink area, there is no recorded evidence of them having stopped to take water here.
Leave your vehicle in the Oak Hill Snow Play Area
parking lot. We made an initial "mistake" heading south from the parking lot following the trail to the snow play support buildings and climbed up Oak Hill. We found it "odd" that there was no mention of Keyhole Sink on any of the signage within the Snow Play Area and decided to retrace our steps and check out the north side of Route 66.
Gazing across the parking lot to the opposite side of Route 66, I could pick out a green gate
interrupting the fence line. As you get closer, signage indicating Keyhole Sink Trail
becomes visible. Mileage is listed at 1 mile from the TH to the Keyhole Sink.
Pass through the gate and follow the blue blazes
marked on the trees in regular intervals. Turns out that this trail is popular with cross-country ski enthusiasts explaining the need for frequent blue blazes as fresh snowfall could make the route a bit of a mystery. The trail follows a gentle incline past some limestone outcrops
. Continue to follow the blue blazes
as the sounds of civilization disappear and the rustling sounds of Quaking Aspen leaves takes over
. There are a number of aspen saplings close to the trail with larger specimens along the incline slopes. Towering Ponderosa Pines dominate the ledges as you notice cliffs beginning to converge into a box canyon. Keyhole Sink must be close by!
Sure enough, just around the corner you come to a fenced area
with a guest register and interpretive sign. The interpretive sign features the aforementioned rock art panel showing deer entering into the box canyon with hunters at the ready along the cliff tops. There is also a sign posted
as a reminder of the effects of thoughtless vandalism on our ancient heritage. No word that the perpetrators have been uncovered.
Sign the guest register and pass through the gate entering the Keyhole Sink
. Dark basalt cliffs standing more than 25 feet high form a natural enclosure and effectively dam the water flow. A large pool of standing water pushes against the far end cliffs. We chose the path heading to the left side of the pool and we could begin to make out a large rock art panel
at its terminus. The rains from earlier in the day made it difficult at first to pick out the rock art examples, but with slow
examination many begin to jump out. The enclosed area also has an abundance of wildflowers and insects. We even discovered some small grass snakes scurrying from underfoot.
When you exit the enclosed area, follow the faint trail along the wooden fence line to the north through the aspen
saplings. There is easy access to the top of the basalt cliffs. From this upward vantage, one can survey the entire Keyhole Sink area. One can imagine waiting from these cliffs for a deer or elk to enter the box canyon...
This is an easy trail that provides some unexpected seclusion while so close to civilization. There's wildflowers and wildlife with a rock art payoff at the end of the trail. What's not to like? I'd also be interested in seeing this area under a fresh blanket of snow. Enjoy