Tijuana (/tiːˈwɑːnə/tee-WHAH-nə; Spanish: [tiˈxwana]) is the largest city in Baja California and on the Baja California Peninsula and center of the Tijuana metropolitan area, part of the international San Diego–Tijuana metropolitan area. As an industrial and financial center of Mexico, Tijuana exerts a strong influence on economics, education, culture, art, and politics. As the city has become a leading center in the country, so has the surrounding metropolitan area, a major industrial and paramount metropolis in northwestern Mexico. Currently one of the fastest growing metropolitan areas in Mexico, Tijuana maintains global city status. As of 2015, the city of Tijuana had a population of 1,696,923.
On the Gold Coast of Baja California, Tijuana is the municipal seat and the cultural and commercial center of Tijuana Municipality, covering 70% of the municipality but with over 80% of its population. A dominant manufacturing center of the North American continent, the city maintains facilities of numerous multinational conglomerate companies. The early 21st century saw Tijuana become the medical-device manufacturing capital of North America. Also a growing cultural center, Tijuana has been recognized as an important new cultural mecca. The city is the most visited border city in the globe; sharing an approximate 24-kilometre-long border (15 mi) with its sister city San Diego, over fifty million people annually cross the border between these two cities. This metropolitan crossing makes the San Ysidro Port of Entry the busiest land-border crossing in the world. It is estimated that the two border crossing stations between the cities proper of San Diego and Tijuana account for 300,000 daily border crossings alone.
Tijuana is the 29th largest city in the Americas and is the westernmost city in Mexico. According to the 2010 census, the Tijuana metropolitan area was the fifth-largest in Mexico, with a population of 1,784,034, but rankings vary, the city (locality) itself was 6th largest and the municipality (administrative) 3rd largest nationally. The international metropolitan region was estimated to be just over five million in 2009 and approximately 5,105,769 in 2010, making it the third largest metropolitan area in the Californias, 19th largest metropolitan area in the Americas, and the largest bi-national conurbation that is shared between US and Mexico. Tijuana is becoming more suburbanized like San Diego; during the 2000s the drug violence had residents moving out of the congested urban core into isolated communities within the municipality and beyond, as evidenced by 2010 Census figures and growth patterns.
Tijuana traces its modern history to the arrival of Spanish explorers in the 16th century who were mapping the coast of the Californias. As the American conquest of northern Mexico ended with the Treaty of Guadalupe Hidalgo, Tijuana's new international position on the border gave rise to a new economic and political structure. The city was founded in July 11, 1889 as urban development began. Often known by its initials, T.J., and nicknamed Gateway to Mexico, the city has historically served as a tourist center dating back to the 1880s.