North Latitude: 35° 0' 0" N (35.0000)
South Latitude: 34° 30' 0" N (34.5000)
East Longitude: 112° 15' 0" W (-112.2500)
West Longitude: 112° 30' 0" W (-112.5000)
The Granite Dells, or locally known as The Dells, are an approximately 1.4-million-year-old Precambrian outcropping of granite located about 5 miles northeast of the city of Prescott, Arizona, USA. According to the official survey report published by the U.S. Geological Survey in 1965, the Granite Dells are approximately five square miles in area in a roughly triangular formation, comprised of Dells Granite, so named for its location and unique composition of the Granite Dells. The granite itself is a medium-grained to course-grained granite with extensive weathering and appearing to be somewhat rounded. The weathered channels are often found to be containing deposits of iron oxide, giving the Granite Dells a rather checkerboard appearance.
At the base of the Granite Dells are two man-made reservoirs: Watson Lake reservoir to the south, and Willow Lake reservoir to the west. These reservoirs are fed by Granite Creek, which runs through the Granite Dells in a generally north-south direction.
Several trails run through the Granite Dells and are open to the public for pedestrian, equestrian, and cyclist use. The Iron King Trail originates in Prescott Valley, Arizona, at the base of nearby Glassford Hill, and follows the decommissioned Santa Fe Railroad's Iron King Railway for approximately 4.3 miles to Prescott through the Granite Dells. The Peavine Trail originates at Watson Lake Park and continues 5.2 miles through the Granite Dells, meeting the Iron King Trail about halfway through the trail loop.
Radon gas levels are known to be elevated in the Granite Dells and should be addressed particularly when local residential development is considered. In 2014, the construction of a master-planned community began in a 1,100-acre parcel of the Granite Dells, aptly named The Dells. Three home builders: Carrington Homes, Mandalay Homes, and Dorn Homes are planning for 3 distinct neighborhoods, comprising a total of 300 homes when development is complete. Sunset Ridge is a large, gated neighborhood offering the largest lots for custom-built homes. The Vistas neighborhood will have a total of 83 custom homes, and The Peaks neighborhood will have 60 homes when construction has finished.
The Granite Dells Preservation Foundation non-profit was established in 2010 to preserve the Granite Dells. This organization works with the Save the Dells Political Action Committee (PAC) to actively preserve the Granite Dells from over-development.
Geology of the Prescott and Paulden quadrangles, Arizona, Professional Paper 467, Medora Louise Hooper Krieger, 1965, U.S.G.S. https://pubs.usgs.gov/pp/0467/report.pdf
RECONNAISSANCE GAMA-RAY SPECTROMETER SURVEY OF RADON-DECAY PRODUCTS IN SELECTED POPULATED AREAS OF ARIZONA, Dudley F. Erner (I), Jonathan D. Shenk, and Jon E. Spencer, Arizona Geological Survey Open-File Report 88-12, 1988,http://repository.azgs.az.gov/sites/default/files/dlio/files/nid885/ofr-88-12.pdf