San Luis Potosí, commonly called SLP or simply San Luis, is the capital of, and most populous city in the Mexican state of San Luis Potosí. The city lies at an elevation of . It has an estimated population of 735,886 inhabitants in the city proper, and a population of approximately 1,021,688 in its metropolitan area which is formed with the neighbour city of Soledad and some other small townships inside the urban area. This makes the metropolitan area of Greater San Luis Potosí the eleventh largest in Mexico.
The city is named after Louis IX of France (also known in Mexico as San Luis Rey de Francia; Saint Louis, King of France), who is the city's patron saint. Potosí was added in reference to the fabulously rich mines of Potosí, Bolivia, discovered some forty years before the city was founded, as the exploitation of silver and gold mines in Cerro de San Pedro near San Luis was the main reason for the founding of the city in 1592.
Nowadays the city is one of the main industrial centres in central Mexico with a prolific manufacturing industry. A number of foreign industries have chosen to invest in San Luis Potosí in the last decades thanks to its strategic location for trade, as the city is located halfway between Mexico City and the United States border, as well as in the middle of the triangle formed by Mexico City and the other two largest cities in Mexico, Guadalajara and Monterrey.
Besides its industry-based economy, recently the city has been promoted as a touristic destination in central Mexico by state and federal programs. San Luis Potosí's historic downtown displays a great mixture of different artistic styles in many buildings and it's a major example of colonial architecture in Mexico. In 2010 the historic center of the city was listed as a UNESCO World Heritage Site within Camino Real de Tierra Adentro.