San Diego, historically inhabited by the Kumeyaay people, is often called the “Birthplace of California.” In 1542, explorer Juan Rodríguez Cabrillo claimed the area for Spain, laying the groundwork for European settlement in Alta California two centuries later. The establishment of the Presidio and Mission San Diego de Alcalá in 1769 marked California’s first permanent European settlement. After becoming part of the Mexican Empire in 1821, San Diego was ceded to the United States following the Mexican–American War in 1848, with California achieving statehood in 1850.

Today, San Diego thrives as a dynamic economic hub. Its largest industries include military and defense, tourism, international trade, research, and manufacturing. The city is home to renowned universities such as UC San Diego, San Diego State University, and the University of San Diego, fostering innovation and education.

San Diego serves as the economic heart of the San Diego–Tijuana region, the Western Hemisphere’s second-most populous transborder metropolitan area, with an estimated five million residents as of 2022. The San Ysidro Port of Entry, connecting the city to Tijuana, is the world’s busiest international land border crossing outside of Asia. Air travel is equally significant, with San Diego International Airport (SAN) holding the distinction of being the busiest single-runway airport in the United States.

Blending a rich historical legacy with modern economic vitality, San Diego continues to play a pivotal role on both national and international stages.