San Juan del Río is a city and administration of the surrounding San Juan del Río Municipality (pop. 208,462) in the central Mexican state of Querétaro.
The city and its municipality have the second-highest population in the state. The municipality has an area of 799.9 km2 (308.8 sq mi).
The city is located on country’s central plateau (altiplano), 50 km (31 mi) southeast of state capital, Santiago de Querétaro, at 20°23′N 99°59′W with an elevation of 1922 m. Although famous for its opals, mined at nearby La Trinidad, it is also an agricultural center (corn, wheat, sugarcane, beans, alfalfa, fruit, and livestock). A number of wineries are also located in the vicinity.
The city was founded on the Feast of Saint John the Baptist June 24, 1531, by Fernando de Tapia, an Otomí chieftain that converted to Catholicism and dropped his Native name Conín. San Juan was one of the first Spanish settlements outside the Valley of Mexico and thus marked the beginning of the colonization of Northern and Western Mexico, including the city of Querétaro, which was founded one month later. The settlement became important since it was an obligated to stop during the rich mining regions of Guanajuato, Zacatecas and San Luis Potosí.
San Juan del Río is connected to Santiago de Querétaro and Mexico City by the mainline freight railway and Federal Highway 57
In what now occupies the municipal area of San Juan del Río, on the bank of the river that bears the same name, discoveries of the ancient Otomí culture who have the ancestry of Chupícuaro have been found, legacies indicating that the area was inhabited around 400 BC. The ancient settlers were sedentary gatherers; carriers of a complex culture and way of life. It is considered one of the oldest social organizations in the Mexican highlands. The Otomí culture made very important advances, especially in the cultivation of maize, beans, pumpkin, and Agave. The Otomí, after having great advantages in agriculture, were grouped in the region around the hill Techimacit (today Barrio de la Cruz); in the glen that forms the riverbed; they built their houses forming the village they called Ixtachichimecapan, which means land of white Chichimecas, and whose chief it was Mexici who later had the Christian name of John.