Gia Định (嘉定) was a province of South Vietnam surrounding Sài Gòn. It was one of the country's main industrial centers.
Gia Định was created in 1832 as part of Six Provinces of Southern Vietnam and split to four smaller provinces in December 1889: Gia Định, Chợ Lớn, Tân An and Tây Ninh.
Đông Nam Bộ (literally "Southeast region") is a region in Southern Vietnam. This region includes one municipality, Ho Chi Minh City; and five provinces: Đồng Nai, Bình Dương, Bà Rịa–Vũng Tàu province, Bình Phước and Tây Ninh. The two south central provinces Ninh Thuận and Bình Thuận are sometimes seen as part of the Southeast region. This region is the most economically developed region in Vietnam. In 2006, this region contributed 148,000 billion VND (equal to $9.25 billion) out of 251,000 billion VND to the state budget. This region is also the most highly urbanized in the country with more than 50% people living in urban areas (while the equivalent figure for Vietnam is just 25%).
Tây Ninh () is a formerly provincial city in Southeastern Vietnam. The new provincial capital is located in Long An Ward, Tây Ninh Province (formerly as Tân An City, Long An Province). Tây Ninh is one of nine provinces and cities in the Southern Key Economic Region (Ho Chi Minh City metropolitan area). Tây Ninh is approximately 90 km (55 miles) northwest of Ho Chi Minh City, the largest city of Vietnam, and 182 km (113 miles) to Phnom Penh, capital of Cambodia; all by National Route 22. As of 2019, the city had a population of 135,254 over the provincial population of 1,169,165 on a total area of 140 km (54 sq mi).