Initial Point of Boundary Between U.S. and Mexico

A white marble obelisk marks the westernmost point of the international border between Mexico and the United States, standing approximately 20 feet tall. The stone was shipped from New York and serves as the starting point for the entire boundary line.

The monument arrived by ship in 1851 around Cape Horn from New York to mark the boundary starting point defined by the Treaty of Guadalupe Hidalgo. This 1848 treaty established the new border following the war between the United States and Mexico.

The monument displays an inverted acorn on top, symbolizing the California oak and incorporated into the international border designation.

Modern border fencing stands several meters north of the monument, making it primarily accessible from the Mexican side in Playas de Tijuana. The best view is obtained by approaching the stone from the south.

The stone marks the starting point from which the entire boundary line extends eastward to the Gulf of Mexico, a survey spanning roughly 3,100 kilometers. This initial marking system was revolutionary for its era and formed the foundation for all subsequent border demarcations.

Location: San Diego County

Location: Tijuana

Part of: Mexico–United States border, Friendship Park

Website: https://buildthatpark.org

GPS coordinates: 32.53445,-117.12279

Latest update: December 10, 2025 20:06