Vientiane, also spelled Viangchan, largest city and capital of Laos, situated on a plain just northeast of the Mekong River. The city’s central river port location in a country relying heavily on its rivers for transportation and its surrounding hinterland of intensive rice cultivation have made Vientiane the major economic centre of Laos. The city has a tropical monsoon climate, every month having an average daytime temperature above 80 °F (27 °C) and more than 80 percent of Vientiane’s annual precipitation on the average falling in the five months May–September.

The town was founded during the late 13th century, and in the mid-16th century the capital of the Lao kingdom (a state known as Lan Xang) was moved to Vientiane from its previous traditional location at Luang Prabang (now Louangphrabang). In 1778 Vientiane came under Siamese control; in 1828 it was sacked and destroyed when the subject Laotian king revolted against Siamese hegemony. From 1899 to 1953, with the exception of the Japanese occupation (1945), Vientiane was in succession the seat of the French governor and the French administrative capital.

Vientiane still has some of its older wooden structures, despite its government offices, foreign embassies, and schools. Its modern industries include brewing, lumber processing, and the manufacture of brick, tile, textiles, cigarettes, matches, detergents, plastic bags, rubber sandals, and iron and steel. The Lao farmers of the surrounding area tend rice, corn (maize), and livestock in some of the best alluvial lowlands of Laos.

Before 1975 the city was the principal stock shipping and slaughtering centre of the country. Since the shift in the country’s import trade from Vietnam to Thailand, Vientiane has replaced Pakxé to the southeast as Laos’s principal port of entry.

The National University of Laos (founded 1995) in Vientiane has faculties of agriculture, architecture, education, and forestry, among others. Ho Phakeo, the national museum, is located in the city, as are the Dongsaphangmeuk Library and the National Library.

At Vientiane the Mekong River is navigable only by small craft; passage to the right bank and the Thai railhead of Nong Khai was solely by ferry until 1994, when a highway bridge was opened. Vientiane has an international airport, and highways link the city with Louangphrabang and Savannakhet in Laos and with Ho Chi Minh City in Vietnam. The Nam Ngum Dam north of Vientiane provides enough hydroelectric power for the surrounding areas and for export to Thailand as well. Vientiane’s outstanding building is the That Luang, a stupa (temple), dating from about 1566 and restored by Lao civil servants under Prince Phetsarath during the French colonial period. Pop. (2003 est.) city, 194,200; (2005 est.) urban agglom., 702,000.