After the Fort was abandoned, the location appeared on the 1860 and 1861 Public Surveys In New Mexico Territory sketch maps of the U.S. General Land Office.
[8] On November 11–12, 1846, 3 miles above what was later the site of Fort Thorn was the camp of Major Philip St. George Cooke and the Mormon Battalion who were tasked by Brig.
Gen. Kerney with explore a route and building a wagon road from the Rio Grande valley to recently captured Alta California.
[9] According to Cooke, his camp lay across the river from the New Mexican settlement of San Diego, and was 258 miles southwest of Santa Fe, New Mexico.
Originally called Cantonment Garland, Fort Thorn was established December 24, 1853 by Captain Israel B. Richardson, under orders of General John Garland, with a garrison of 3rd U.S. Infantry from abandoned Fort Webster, on the right bank of the Rio Grande midway between Santa Barbara and the point where Cookes Wagon Road turned west from the Rio Grande.
The fort also had a 3.5 mile long acequia that brought water from the Rio Grande to irrigate the post's farms and powered a sawmill.
[12] Its agent was Dr.Michael Steck, trusted by Apache leaders and of whom Army officers in the New Mexico command wrote in a letter to president Peirce recommending his appointment, as having "knowledge of the country, and of the Indians, their language and habits."