Interim Geologic Map of the Mills Junction quadrangle, Tooele County, Utah (OFR-784DM)

By: Emily J. Kleber, and Adam I. Hiscock

The Mills Junction 7.5-minute quadrangle is in Tooele County, Utah. The quadrangle is centered along the southern margin of the south arm of Great Salt Lake and includes the Eardley Spit, a ~3.5-mile-long (5.6 km) east-west-trending spit with about 6 feet (1.8 m) of relief. Just south of the modern Great Salt Lake shoreline, extensive evaporative ponds created to harvest salt from Great Salt Lake obscure geologic deposits. Many of these areas have been developed into wetlands for migratory and native birds. The evaporative ponds are bounded by a Union Pacific mainline and Interstate 80, which are both critical transportation lines through northern Utah. The study area includes the Lake Point interchange, which directs commercial railroad and all vehicle traffic into Tooele Valley. The quadrangle includes the rapidly developing urban areas of Lake Point, Stansbury Park, and recently incorporated Erda. Water drains to Great Salt Lake across the Mills Junction quadrangle from various springs and spring complexes, including Mill Pond spring (historically known as “Twin Springs”), Dunne’s Pond spring (also known as “Factory/Dunne’s Pond spring complex”), and several unnamed springs and artesian wells. 

Other Information:
Published: 2026
Pages: 11
Plates: 2
Scale: 1:24,000
Location: North Western Utah
Media Type: Paper Publication