In a land area of 30,594.90 square kilometers, the diocesan territory covers northern central provinces of Ha Tinh, Nghe An and Quang Binh.
The diocese is surrounded by Thanh Hoa province in the north, the sea in the east, Quang Tri province in the south and Laos in the west.
Ha Tinh province's capital is Ha Tinh city, Vinh city is the capital of Nghe An province and Dong Hoi city is the capital of Quang Binh province.
Kinh or majority Vietnamese and some ethnic minority groups of Chut, Ede, Hmong, Kho Mu, O Du, Man, Muong, Tay, Thai and Tho.
Vietnamese is mainly used in the diocesan territory. Local dialects are in use among ethnic groups.
Foreign Jesuits worked in the three provinces as early as in 1629. There were many parishes and Church facilities serving thousands of local Catholics in 1634. Many local Catholics and foreign missioners were killed during religious persecution by soldiers.
Nam Dang Ngoai (South Tonkin) vicariate was established in 1846. Then it had 66,350 Catholics at 18 parishes served by 35 Vietnamese priests, four foreign priests, 75 catechists, 69 seminarians, 220 Religious.
From 1846 to 1946, the vicariate was headed by five foreign bishops who established many parishes, built churches, schools, hospitals, the bishop's house, seminaries and composed prayers books in the local language.
The vicariate was renamed after Vinh vicariate in 1924 and elevated to diocese in 1960, when the Vietnam Bishops' Conference was established. The late Bishop John Baptist Tran Huu Duc was the first Vietnamese bishop of the diocese.
After French troops were defeated by communists in 1954, estimated 50,000 priests, Religious and Catholics had to flee to southern Vietnam. In 1966-1972, the local Church was badly affected by the Vietnam War. Many local churches were collapsed or damaged, Catholics had to move to other places and religious activities were limited.
In 1988, the local Church reopened its major seminary that gives priestly formation to students from Vinh and Thanh Hoa dioceses.
In recent years, the local Church has built new churches and facilities and revived old parishes and associations. The diocese aims to train catechists, lay leaders, priests and Religious. Diocesan committees and advisory, presbyteral, pastoral and finance councils are established. Funds for pastoral activities and flood victims are created.
Another its top priority is evangelization. Local Catholics are urged to evangelize themselves, their families and other people. They are also asked to reach out to people, work for the common good, live out their faith publicly, bravely go beyond their old faith practices and see signs of time to reach out to other people.
Vinh diocese is suffragan of Ha Noi archdiocese. Its titular is the feast of Assumption of the Blessed Virgin Mary, August 15.
Main vehicles used in the area include motorbikes, bicycles, buses, boats, trains and airplanes. Vinh Airport, that is five kilometers away from Vinh city, has flights to and from Ha Noi and Ho Chi Minh city.
The diocese has a tropical climate under the influence of the East Asia monsoon. It has two seasons - dry season and rainy season. Three provinces have different temperatures.
In Ha Tinh province, the temperature in winter is 18-22 degrees Celsius and in summer is 15.5-33 degrees Celsius. The rainy season lasts from August to November and the dry season lasts from December to July.
Nghe An province has the average annual temperature of 23-24 degrees Celsius.
Quang Binh has the dry season lasting from April to August and the rainiy season lasting from September to March. Its average annual rainfall is 2,000-3,000 millimeters and average annual temperature is 24-25 degrees Celsius.
In 2010, the annual per capita income was 14.16 million dong (US$677.5) in Nghe An province, 14 million dong (US$670) in Quang Binh province and 11 million dong (US$526) in Ha Tinh province.
Local people mainly cultivate crops, catch fish and produce salt from sea water and handicrafts. Some do business in Laos.
The diocese has followers of Buddhism, Protestantism and indigenous faiths of Cao Dai and Hoa Hao.