San Ysidro has come to be known as "The Gateway to the Americas" because of its location at the southernmost portion of California. Together with Tijuana, Mexico, it is considered the busiest border crossing city in the world.
The construction of Interstate 5 and Highway 805 during the 1970s and 80s gave San Ysidro the title of biggest port of entry worldwide.
San Ysidro's history dates back to the 1700s. At the time, the Kumeyaay Indians occupied what we know as San Diego. Franciscan Priest Junípero Serra, who came from the Loreto mission in Baja, established the current California Missions on those same lands.
In the early 1900s, centuries after Fray Junípero Serra had first arrived to California, a settlement was established by William Smythe. This settlement was named "Little Landers Colony." Years later it was renamed San Ysidro in honor of the farmer's patron saint. In 1957 it was annexed to the City of San Diego.