city, capital of San Juan provincia (province), west-central Argentina. It lies along the San Juan River and is enclosed by Andean foothills on three sides. Founded in 1562 by Juan Jufré y Montesa, governor of the captaincy general of Cuyo, the city was moved in 1593 to its present site, 2 miles (3 km) south, because of floods; it is now protected by an embankment. Because it was on the fringe of Spanish-held territory, it was originally named San Juan de la Frontera. Early in the 18th century, Jesuits built a cathedral and a convent, both of which were destroyed, along with most of the city's other buildings, in a severe earthquake in 1944. Reconstruction has given San Juan a modern appearance.

The processing of meat, wines, fruits, and grains is the main economic activity. San Juan was the birthplace of Domingo Faustino Sarmiento (Sarmiento, Domingo Faustino) (Argentine educator and president from 1868 to 1874), and his home, which contains a museum and library, was declared a national monument in 1910. Pop. (2001) 112,778.

city, southwestern Dominican Republic. It lies on the San Juan River, an affluent of the Yaque del Sur River, northwest of Santo Domingo city. The Spanish explorer Diego Velázquez founded San Juan in 1508 by royal decree on the site of the Taino Indian capital, then ruled by Chief Caonabo. The settlement floundered until 1764, when an influx of ranchers revitalized the area. During the early 19th century, San Juan witnessed a series of Dominican-Haitian battles, followed by Creole uprisings for independence from Spain. The Battle of Santomé (1844), which achieved Dominican independence, was fought nearby; it is commemorated by a monument. In addition to cattle, the economic activities of the city focus on the production of rice, coffee, corn (maize), fruit, and potatoes. Pop. (2002) urban area, 70,969.

In 1508 the Spanish explorer Juan Ponce de León (Ponce de León, Juan) founded the original settlement, Caparra, on the almost landlocked harbour just to the west of the present metropolitan area. In 1521 the settlement was moved to a rocky islet at the harbour entrance. Casa Blanca (“White House”) was begun that same year and was owned by Ponce de León's family until the late 18th century. In 1533 the Spanish began construction of massive fortifications in response to attacks by native Taino and by European powers. The bulwark-palace known as La Fortaleza, built near Casa Blanca, was the first of the new defenses (it now houses the governor's mansion). San Felipe del Morro castle (also called El Morro) was constructed next, on a high bluff overlooking San Juan Bay.

The main campus of the University of Puerto Rico (1903) is located in the Río Piedras barrio (ward) of San Juan. The medical campus and other facilities of the university also are located in San Juan. In 1957 the university became the home of the Casals Festival (now held in Santurce, San Juan's chief residential suburb), founded by Pablo Casals. The city's other educational institutions include the University of the Sacred Heart (1935) and a campus of the Inter-American University of Puerto Rico (1912). The Puerto Rico Museum of Art, combining a new five-story structure with a former hospital building, opened in 2000. Notable annual events in addition to the Casals Festival are the San Sebastian Street Festival in January and the San Juan Bautista (St. John the Baptist) Festival in June.

county, northwestern New Mexico, U.S., bordered on the north by Colorado and on the west by Arizona; it also touches Utah at its northwestern tip at the only location in the United States (called the Four Corners) where four states meet. San Juan county is a scenic, semiarid area in the Navajo section of the Colorado Plateau. The centre of the county contains buttes, broken red sandstone mesas, angular volcanic rocks—including the landmark Ship Rock—and mountains rising dramatically from the basically flat landscape, with arroyos and canyons gouged by streams that have mostly dried up. The Chuska Mountains rise to more than 9,000 feet (2,700 m) in the southwest. The San Juan River, at Lake Navajo, forms the county's northeastern boundary, then receives the Las Animas River and flows in a long curve through the county. The western half of San Juan county is occupied by the Navajo Indian Reservation and, in a small area near Colorado, the Ute Mountain Indian Reservation. Chaco Culture National Historic Park, Aztec Ruins National Monument, Angel Peak State Recreation Area, and Navajo Lake State Park are all located in the county.

Ancestral Pueblo (Ancestral Pueblo culture) (Anasazi) peoples built the pueblo at Aztec Ruins National Monument early in the 12th century; by the 16th century, Pueblo and Navajo Indians were living in the region. War between Navajos and whites was intermittent for over two centuries. The Spanish, then the Americans forced Navajos into slavery, and in 1864 American soldiers led by Colonel Kit Carson forced over 7,000 Navajos to make the “long walk” to the notorious Bosque Redondo, where they lived under great privation. Four years later the vast Navajo reservation was established in New Mexico and Arizona. San Juan county was established in 1887.

The Navajo nation owns almost 60 percent of San Juan county and the U.S. government about 29 percent. In the 20th century, the production of coal, natural gas, and petroleum brought prosperity to the region. Federal expenditures and tourism also contribute to the economy. Aztec is the county seat, and the town of Bloomfield and the city of Farmington are other population centres. Area 5,514 square miles (14,282 square km). Pop. (2000) 113,801; (2007 est.) 122,427.

provincia (province), west-central Argentina. It is separated from Chile on the west by the Andean cordillera, whose peaks average between 14,800 and 16,400 feet (4,500 and 5,000 metres) in elevation. Snow-fed rivers from the Andes dissect its mountainous western terrain. Three main rivers, the Bermejo, Jáchal, and San Juan, all used for irrigation, discharge into marshes in the semiarid southeastern portion of the province.

San Juan was settled in the late 16th and early 17th centuries by small numbers of Spanish agriculturists, Dominicans, and Jesuits from Chile. A part of the old Cuyo region, it remained a sparsely populated area exporting wine and dried fruits that were produced in its irrigated valleys. In 1776 control over San Juan passed from the Chilean captaincy general to the Río de la Plata viceroyalty. San Juan declared its own status as a province in 1825. The province was the epicentre of severe earthquakes in 1776, 1944, and 1977.

Grapes grown for both the table and wine occupy half of the cultivated land; olives, apples, barley, and onions are also raised, together with sheep and cattle. San Juan is rich in copper reserves but exploitation is limited. Economic activity in the city of San Juan, the capital of the province, and other urban centres is concentrated on food processing. The province is linked to Chile, with which much of its trade is carried on, by one local road across the Andes. Area 34,614 square miles (89,651 square km). Pop. (2001) 620,023.