Monumental in San Diego in San Diego County, California — The American West (Pacific Coastal)
Boundary Marker Number 258
Photographed by Michael Kindig, August 11, 2007
1. Boundary Marker Number 258 Marker
National Register Number: 1974000550
Near this site the initial point of the boundary between the United States of America and the Republic of Mexico was established October 10, 1849.
Today, the flag of the United States of America is again raised to symbolize friendship between the peoples of the United States and Mexico and to commemorate the establishment of a State Park adjacent to this point on the International Border.
Boundary Marker Number 258 was placed
on the National Register of Historic
Places September 6, 1974
Erected 1974.
Topics and series. This historical marker is listed in this topic list: Notable Places. In addition, it is included in the National Register of Historic Places (NRHP) series list. A significant historical date for this entry is October 10, 1849.
Location. 32° 32.073′ N, 117° 7.367′ W. Marker is in San Diego, California, in San Diego County. It is in Monumental. It can be reached from Monument Road. The marker is located at Border Field State Park. Touch for map. Marker is in this post office area: San Diego CA 92154, United States of America. Touch for directions.
Regionally, this marker is in California’s Peninsular Ranges. It is also on the American Pacific Coast. Globally, it is in North America, on the Ring of Fire, in the Pacific Rim, in the Western Hemisphere, in the Western World, and in the Anglosphere. Historically, it finds itself in what was once New Spain and also Mexicos Alta California.
Other nearby markers. At least 8 other markers are within 11 miles of this marker, measured as the crow flies: Montgomery Memorial (approx. 4.4 miles away); National City Depot (approx. 8.7 miles
this page online
Also see . . .
1. Border Field State Park. California State Parks website entry:
At the very southwest corner of America is a monument marking the border between Mexico and California. When California became a territory at the end of the Mexican-American War, an international border became a necessity. American and Mexican survey crews determined the boundary and the monument of Italian marble was placed in 1851 to mark the original survey site. Today the monument stands in the shadow of the Tijuana Bull Ring and still delineates the border between the United States and Estαdos Unνdos Mexicanos. (Submitted on January 23, 2012.)
2. California SP Initial Point of Boundary Between U.S. and Mexico. National Register of Historic Places Inventory - Nomination Form, 1974
Monument No. 258 was first established(Submitted on July 17, 2025, by Douglass Halvorsen of Klamath Falls, Oregon.)as a cairn of rocks in 1849 following the signing of the Treaty of Guadalupe-Hidalgo. A white marble shaft was manufactured in New York, transported around the Horn on the USS Supply to San Diego, and erected and dedicated at the site in June, 1851. The marble monument was an obelisk about 20 feet in height, resting on a marble pedestal. On its top was an inverted acorn to symbolize the strength and stature of the California live oak tree.Photographed by Michael Kindig, August 11, 20072. Border Fence
In 1894 it was found that the initial monument had become so mutilated by visitors that its outlines were nearly destroyed, and its inscriptions partly obliterated. The Barlow-Blanco Commission had the monument renovated in San Diego, reconstructed at the site, and protected it with an enclosure in 1894. Excepting for normal wear and tear and some slight vandalism, the marble monument as reconstructed in 1894 still stands today at its original site.
It should also be noted that Monument No. 258 is the westernmost boundary marker on the international boundary between the United States and Mexico and, as such, has since its erection and will throughout the future mark the southwestern corner of the Continental United States.
Pursuant to President Nixon's "Legacy of Parks," Mrs. Nixon, in August of 1971, turned over 372 acres of surplus Navy land, formerly known as "Border Field," to the people of Californiaas a beach park. The area is now commonly known as "Border State Park." The park land is separated from the international boundary and the site of Monument No. 258, only by a 60-foot strip adjacent and parallel to the international boundary reserved for the United States Department of Justice.Photographed by Michael Kindig, Boundary o3. Boundary Marker Number 258 (1894)NORTH FACE “Boundary of the United States. The destruction or displacement of this monument is a misdemeanor punishable in the United States or Mexico.”
WEST FACE “Initial point of Boundary between the United States and Mexico. Established by a joint commission on October A.D. 1848 agreeable to the Treaty dated at the City of Guadalupe-Hildago February 2 A.D. 1851. John B Weller U.S. Commissioner, Andrew B. Gray, U.S. Surveyor.”
EAST FACE “Reconstructed August 1894 by the International Boundary Commission operated by the conventions of 1882 and 1889.”
Additional commentary.
1. Boundary Marker Number 258 is currently inaccessible on the US side
The Border Field State Park website states the following (as of 7/17/25): "Access to the Border Monument at Friendship Circle - Friendship Park is currently closed. For more information, please contact the Border Patrol Public Information Office: 619-216-4182. Border Monument number 258 can be viewed from Monument Mesa, however there is no close access because it is now behind two border fences."
A very historical monument is now inaccessible on the US side due to border restrictions. Hopefully, relations between the US and Mexico improve down the road to be able to visit this marker in person. I would assume if you are able to cross the border into Mexico with a passport, you can visit the monument up close, based on Google Map views.
Photographed by Michael Kindig, August 11, 2007
4. Boundary Marker Number 258 (1894)
Photographed by Michael Kindig, August 11, 2007
5. Border Field State Park
National Register of Historic Places Nomination Form, circa 1973
6. Boundary Marker Number 258 Marker
Credits. This page was last revised on March 5, 2026. It was originally submitted on January 13, 2012, by Michael Kindig of Elk Grove, California. This page has been viewed 1,665 times since then and 83 times this year. Photos: 1, 2, 3, 4, 5. submitted on January 13, 2012, by Michael Kindig of Elk Grove, California. 6. submitted on July 17, 2025, by Douglass Halvorsen of Klamath Falls, Oregon. • Syd Whittle was the editor who published this page.
