The Keyhole, Larimer County, Colorado
Photo by Jay Wilbur
NABSQNO 13T-486235-4474730. The Keyhole is the largest of several natural arches that have eroded through a fin of Dakota sandstone called the Devils Backbone. It is a fin natural arch. The Devils Backbone is located about 5 miles west of Loveland in Larimer County, Colorado. The Keyhole and the other, smaller arches are visible from US Highway 34.
Vreeland included The Keyhole as number 18-28 in his catalog and reported a span of about 20 feet.