La Paz, officially known as Nuestra Señora de La Paz, is the de facto capital of Bolivia and is the seat of government of the Plurinational State of Bolivia. With an estimated 816,044 residents as of 2020, La Paz is the third-most populous city in Bolivia. Its metropolitan area, which is formed by La Paz, El Alto, Achocalla, Viacha, and Mecapaca makes up the second most populous urban area in Bolivia, with a population of 2.2 million, after Santa Cruz de la Sierra with a population of 2.3 million. It is also the capital of the La Paz Department.

The city, in west-central Bolivia 68 km (42 mi) southeast of Lake Titicaca, is set in a canyon created by the Choqueyapu River. It is in a bowl-like depression, part of the Amazon basin, surrounded by the high mountains of the Altiplano. Overlooking the city is the towering, triple-peaked Illimani. Its peaks are always snow-covered and can be seen from many parts of the city. At an elevation of roughly 3,650 m (11,975 ft) above sea level, La Paz is the highest capital city in the world. Due to its altitude, La Paz has an unusual subtropical highland climate, with rainy summers and dry winters.

La Paz was founded on 20 October 1548, by the Spanish conquistador Captain Alonso de Mendoza, at the site of the Inca settlement of Laja as a connecting point between the commercial routes that led from Potosí and Oruro to Lima; the full name of the city was originally Nuestra Señora de La Paz (meaning Our Lady of Peace) in commemoration of the restoration of peace following the insurrection of Gonzalo Pizarro and fellow conquistadors against the first viceroy of Peru. The city was later moved to its present location in the valley of Chuquiago Marka. La Paz was under Spanish colonial rule as part of the Viceroyalty of the Río de la Plata, before Bolivia gained independence. Since its founding, the city was the site of numerous revolts. In 1781, the indigenous leader and independence activist Túpac Katari laid siege to the city for a total of six months, but was finally defeated. On 16 July 1809, the Bolivian patriot Pedro Domingo Murillo ignited a revolution for independence, marking the beginning of the Spanish American Wars of Independence, which gained the freedom of South American states in 1821.

As the seat of the government of Bolivia, La Paz is the site of the Palacio Quemado, the presidential palace. It is also the seat of the Bolivian legislature, the Plurinational Legislative Assembly, and numerous government departments and agencies. The constitutional capital of Bolivia, Sucre, retains the judicial power. The city hosts all the foreign embassies as well as international missions in the country. La Paz is an important political, administrative, economic, and sports center of Bolivia; it generates 24% of the nation's gross domestic product and serves as the headquarters for numerous Bolivian companies and industries.

La Paz is also an important cultural center of South America, as it hosts several landmarks belonging to the colonial times, such as the San Francisco Church, the Metropolitan Cathedral, the Plaza Murillo and Jaén Street. La Paz is also situated at the confluence of archaeological regions of the Tiwanaku and Inca Empire. The city is renowned for its unique markets, particularly the Witches' Market, and for its vibrant nightlife. Its unusual topography offers unique views of the city and the surrounding mountains of the Cordillera Real from numerous natural viewing points. The city is considered to be a unique metropolitan structure, where a majority of the city has been built into the canyon of the Chuqiyapi and Irpavi Rivers. La Paz is also home to the largest urban cable car network in the world. In May 2015, it was officially recognized as one of the New 7 Wonders Cities together with Beirut, Doha, Durban, Havana, Kuala Lumpur and Vigan. La Paz is listed on the Global Cities Index 2015, and is considered a global city type "Gamma" by Globalization and World Cities Research Network (GaWC).