Creation of 247-square-mile Lake Mead inundated 500 prehistoric Native American pit houses and the entire historic town of St. Thomas.
ConsequenceCompletely severed historical road connections between Las Vegas and northern Arizona.
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USGS HISTORICAL TOPO SCRUBBER
The Roads and Towns That Disappeared Beneath Lake Mead
How the 1935 completion of Hoover Dam drowned the 1865 Mormon pioneer settlement of St. Thomas under 60 feet of water, and how the 2000–2026 megadrought resurrected its ruined stone streets.
36.4528° N 114.3700° W 4 survey generations
1895 / 1:250,000ILLUSTRATIVE SETTING
READING 1 OF 4
1895 St. Thomas & The Muddy River Basin
Dry desert valley with agricultural orchards along the Muddy and Virgin Rivers; Arrowhead Trail highway hub.
Present in 1895
- Town of St. Thomas post office
- Salt mine wagon roads
- Virgin River ferry crossing
Absent from this record
- Hoover Dam
- Lake Mead
- Overton Arm
USGS St. Thomas 1:250,000 Reconnaissance MapUSGS (Powell Survey lineage)
THEN → NOW
1895 2026
Severe reservoir retreat: St. Thomas completely dry and walkable, surrounded by white bathtub ring.
PRESENT IN 2026
- St. Thomas Archaeological Trail
- Abandoned boat ramps ending 800 ft from water
- Exposed Muddy River channel
- Overton Beach Marina (demolished due to water retreat)
What changed. What remains.
READ THE TRANSFORMATIONSThe 2000–2026 climate megadrought reduced reservoir volume by 70%, re-exposing drowned infrastructure as archaeological ghost geography.
ConsequenceModern topographic maps had to re-survey exposed shorelines as land rather than navigable water.