Image Credit: The Juniper Lab
Founded by Mormon pioneers in 1865 in what they thought was Utah/Arizona territory St. Thomas was great farming ground right at the confluence of the Muddy River and the Virgin River. The rivers then flowed 22 miles south down to the Colorado River.
Before the Mormons arrived Ancestral Puebloans (formerly known as the Aansazi) inhabited the area and built what is now known as The Lost City. When the federal government created Lake Mead with the finishing of Hoover Dam (aka Boulder Dam) the water covered the city. Before the inundation archaeologists excavated whatever they could and placed the artifacts in the nearby Lost City Museum.
Image Credit: UNLV
Over the years the town grew to around 500 people with a school, grocery store, post office, and more. Settlers built several garages to cater to people driving automobiles on the Arrowhead Trail.
Now, with drought and increased water demands St. Thomas is once again above the water and dry. The Park Service created a short trail down to the old settlement where hikers can explore the old town.