The Tri-State Monument (aka Three Corners) marks the location of the Southwest Corner of Utah, the Northwest Corner of Arizona, and the East line of Nevada.
The Tri-State Monument marks the location of the Southwest Corner of Utah, the Northwest Corner of Arizona, and the East line of Nevada.
Tri-State Monument GPS Coordinates: 37.00016, -114.05015
History of the Tri-State Monument
1870 – Under the General Land Office Contract dated August 16th, 1870, Isaac P. James, Astronomer and Surveyor, surveyed the Eastern boundary of the State of Nevada. The survey commenced October 17, 1870, and completed December 26, 1870. During the survey Mr. James established at the 37th Parallel North Latitude, the corner of Utah, Arizona, and Nevada, at mile 298 and 56.00 chains from his Initial Point to the north on the Central Pacific Railroad.
NOTE: This original monument is displayed on the second level of the Washington County Administration Building. The middle portion of the 6-foot shaft was cut off and removed to display both monuments.
1900 thru 1901 – Under General Land Office Contract dated October 13th, 1900, Howard B. Carpenter, U.S. Surveyor and Astronomer, was directed to survey the boundary line between the State of Utah and the Territory of Arizona. The survey commenced March 24, 1901, and completed July 1, 1901.
Learning from local people living on the Virgin River near where it is crossed by the line between Nevada and Arizona, that old corners on the line were still in existence and that the sandstone shaft erected by Mr. James in 1870 to mark the 37th parallel was still standing, Mr. Carpenter proceeded out from St. George, Utah and Beaver Dam Wash, in Arizona and found the 1870 James state line corners. After astronomical observations it was determined that the “James Monument was 111.51 chains too far north (7,359.67 feet or 1.39 miles). Therefore, pursuant to instructions I destroyed the James corner and proceeded to establish the initial corner at the intersection of the 37th Parallel with the James line.”
“At the intersection of the 37th parallel north latitude with the James line I set a red sandstone shaft 6 ft. long 16 ins. broad and 12 ins. thick, dressed 8 ins. down from the top, diagonally in the ground, for the Initial Monument, marked with letters 1 1/2 ins. square deeply graven in the stone NEVADA on the N.W. UTAH on the N.E. ARIZONA on the S.E. and INtl. MONT. 37 N. L. 1901 on the S.W. faces. Raised a mound of stone 5 1/2 ft. base 2 1/2 ft. high around the shaft and dug pits 36X36X18 ins. N. E. and S. of corner 6 ft. dist. No trees within limits.”
In 2017, the Utah Council of Land Surveyors, in cooperation with the BLM replaced the sandstone monument with a granite monument seen today. The original sandstone monument with 1:70 markings from the other end are on display at the Washington County Administration Building in St. George, Utah.
The Tri-State Monument can easily be reached from Mesquite, NV or from UT near Gunlock Reservoir
Other destinations in the area include naming & birthing cave close to Gunlock Reservoir (GPS Coordinates 37.27938, -113.84752) and the Cedar Pocket Sinkhole (GPS Coordinates 36.97314, -113.87361).
