Jeffery City in Fremont County, Wyoming — The American West (Mountains)

The Rise and Fall of Wyoming's Yellowcake Industry Gas Hills and Crooks Gap Uranium Districts

Photographed by Jimmy Emerson, September 6, 2025

1. The Rise and Fall of Wyoming's Yellowcake Industry Gas Hills and Crooks Gap Uranium Districts Marker

Inscription. Although uranium discoveries occurred throughout Wyoming beginning in the early 1900s it was not until 1948, when the Atomic Energy Commission guaranteed a market for yellowcake (processed uranium), that prospecting started in earnest. In September 1958, Nell McNeice and his wife Maxine first discovered uranium in the Gas Hills. Today, a plaque marks Discovery Hill. He quickly found partners and developed the Lucky Mc mining properties. More activity followed. with a hot discovery in Crooks Gap later the same year, and Jeffrey City was born. Before the uranium bust, Jeffrey City boasted a population over 4000 people.

By 1955, more than 7,000 mining claim were filed in Fremont County alone. Just north of Jeffrey City, the Split Rock Mill started operation in 1957. More mills sprang up in the Gas Hills and at Riverton. In the 1950s man camps and mining towns blossomed in the remote Gas Hills Mining District, with the population peaking at nearly 3,000 people. Mine haul roads connected the mining settlements, and uranium flourished, in the 1950s and 1960s. A downturn in 1973 depopulated the towns in the Gas Hills.

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Then, when demand for Wyoming's yellowcake fell in the mid-1980s, came the bust. Today the camps and towns are ghost towns, with the school, bar, grocery, and post office torn down, mobile homes moved away, and dirt streets overgrown. The huge mines were closed, demolished, and reclaimed to grassland. Little evidence remains of the Gas Hills-Crooks Gap uranium boom. Although uranium mining is only a fraction of what it was in 1980, there are hints that the next boom may be just around the corner.

Erected by Wyoming Historic Mine Trail.

Topics. This historical marker is listed in this topic list: Industry & Commerce. A significant historical year for this entry is 1953.

Location. 42° 48.631′ N, 107° 37.04′ W. Marker is in Jeffery City, Wyoming, in Fremont County. It is on Dry Creek Road near Wyoming State Highway (Route 136), on the right when traveling north. Touch for map. Marker is in this post office area: Jeffrey City WY 82310, United States of America. Touch for directions.

Regionally, this marker is in Wind River Country.

It is also in the American Mountain West.

Globally, it is in North America,

the Rocky Mountains,

Photographed by Jimmy Emerson, September 6, 2025

2. The Rise and Fall of Wyoming's Yellowcake Industry Gas Hills and Crooks Gap Uranium Districts Marker

the Western Hemisphere,

the Western World,

and the Anglosphere.

Other nearby markers. At least 2 other markers are within walking distance of this marker: The Yellowcake Boom (a few steps from this marker); Gas Hills- Crooks Gap Uranium Mining District (a few steps from this marker).

More about this marker. Located about 1/10 of a mile north of the junction of WY 136 and Fremont County Rd 5 (Ore Road) after it changes name to Dry Creek Road

Credits. This page was last revised on September 21, 2025. It was originally submitted on September 6, 2025, by Jimmy Emerson of Dalton, Georgia. This page has been viewed 79 times since then and 34 times this year. Photos: 1, 2. submitted on September 6, 2025, by Jimmy Emerson of Dalton, Georgia. • Andrew Ruppenstein was the editor who published this page.