In a land area of about 74,195 square kilometers, the diocesan territory covers Bolikhamxai, Houaphan, Vientiane and Xiangkhoang provinces, as well as Vientiane capital prefecture.
In the vicariate's area, the population is about 2,417,000 in June 2017, mainly Buddhists. The population of the whole country was estimated at 7 million. Most residents are lowland Lao, with tribal minorities. There are substantial numbers of ethnic Vietnamese and Chinese.
Mainly Lao, but also various ethnic minority dialects are in use.
Till the middle of the 13th century the Lao tribes who had migrated from Southern China accepted Buddhism of the Theravada School as their religion. During the following centuries, Buddhist monks (the Sangha) exercised a strong influence on Laotian society. In popular Buddhism the traditional belief in guardian spirits (phi) and the wide-spread rites of of ancestor veneration mingled with Buddhist beliefs. During the 18th and 19th century, the Kingdom of Laos repeatedly was attacked and dominated by its neighbour Vietnam, but even more by its other neighbouring country, Siam. In 1893 the French entered Laos and turned Laos into a French Protectorate and de facto colony of France. The Laotian kings lost more of their political power, but managed to retain many other privileges.
From 1630 onwards, Catholic missionaries made several attempts to enter the country and to preach the gospel in Laos. Most missionary endeavours, however, remained episodes, because they did not result in the founding of a local Church. The first missionaries were Jesuits who reached Laos from Tongking.
The evangelization efforts of the missionaries of the Paris Foreign Mission Society (M.E.P.), who came to Laos in 1878, were more successful. They succeeded in building up an indigenous Church in Laos. Traditionally, Dec. 8, 1885 is accepted to have been the date of the birth of the Catholic Church in Laos, because on this day the first mission station in the then Kingdom of Laos was founded on the island Ban Dorn Don in the river Mekong.
Since 1935, also Oblate Fathers (OMI) came to Laos and concentrated their missionary work mostly in the tribal areas in the mountains, in the north of the country.
Before, in 1899, the Apostolic Vicariate of Laos was founded, from which in 1950 the Apostolic Prefecture Thakhek was separated which later, in 1958, was raised to an Apostolic Vicariate. At that time, the number of Catholics in Laos had reached 23,764 Catholics. It took a long time, before in 1963 the first indigernous Laotian was ordained to the priesthood.
Thakhek signifies in the Laotian language "landing place of foreigners" and thus keeps the memory alive that the foreign Catholic missioners built there their first mission station, from which further missionary activities were started.
A decade later, in 1974, the first Laotian priest was consecrated a bishop. Between 1952-1967, an ecclesiastical restructuring took place and the Catholic Church in Laos was divided into four Apostolic Vicariates: Vientiane (1952), Luang Prabang (1963), Savannakhet (1963) and Pakse (1967).
The country's main north-south highway runs along the western part of the territory. Paved roads outside town areas are limited. A 3.5-kilometer long meter-gauge rail line belonging to the State Railway of Thailand runs across the Thai-Lao Friendship Bridge over the Mekong River. The country's main international airport is in Vientiane. International flights, however, are limited to Bangkok, Hanoi and Kunming. Vientiane is nevertheless the domestic hub of the country.
Tropical monsoon with three seasons -- hot and dry (March-June), rainy (July-October), cool and dry (November-February).
All newspapers are published by the government, including an English-language and a French-language paper.
Mainly hilly and mountainous. The Mekong river runs along the western part of the territory. Picturesque karst limestone formations, one of the biggest in Southeast Asia, are located in Bolikhamxai province. An extensive network of caves in Houaphan province.