InVietNam.org

1976: Vietnam had 38 provinces and cities.

1978: Cao Lạng province was split into Cao Bằng and Lạng Sơn provinces.
(Vietnam now had 39 provinces and cities.)

1979: Vũng Tàu-Côn Đảo Special Zone was established (equivalent to a province).
(Vietnam now had 40 provinces and cities.)

1989: Bình Trị Thiên province was split into Quảng Bình, Quảng Trị, and Thừa Thiên Huế provinces.
Nghĩa Bình province was split into Quảng Ngãi and Bình Định provinces.
Phú Khánh province was split into Phú Yên and Khánh Hoà provinces.
(Vietnam now had 44 provinces and cities.)

1991:
Hoàng Liên Sơn province was split into Yên Bái and Lào Cai provinces.
Hà Tuyên province was split into Hà Giang and Tuyên Quang provinces.
Hà Sơn Bình province was split into Hà Tây and Hoà Bình provinces.
Hà Nam Ninh province was split into Nam Hà and Ninh Bình provinces.
Nghệ Tĩnh province was split into Nghệ An and Hà Tĩnh provinces.
Gia Lai - Kon Tum province was split into Gia Lai and Kon Tum provinces.
Thuận Hải province was split into Ninh Thuận and Bình Thuận provinces.
Hậu Giang province was split into Cần Thơ and Sóc Trăng provinces.
Cửu Long province was split into Vĩnh Long and Trà Vinh provinces.
Three districts of Đồng Nai province were merged with the Vũng Tàu-Côn Đảo Special Zone to form Bà Rịa-Vũng Tàu province.
(Vietnam now had 53 provinces and cities.)

1996:
Vĩnh Phú province was split into Vĩnh Phúc and Phú Thọ provinces.
Bắc Thái province was split into Bắc Kạn and Thái Nguyên provinces.
Hà Bắc province was split into Bắc Ninh and Bắc Giang provinces.
Nam Hà province was split into Hà Nam and Nam Định provinces.
Hải Hưng province was split into Hải Dương and Hưng Yên provinces.
Quảng Nam Đà Nẵng province was split into Quảng Nam province and Đà Nẵng City.
Sông Bé province was split into Bình Dương and Bình Phước provinces.
Minh Hải province was split into Cà Mau and Bạc Liêu provinces.
(Vietnam now had 61 provinces and cities.)

2004:
Đắk Lắk province was split into Đắk Lắk and Đắk Nông provinces.
Cần Thơ province was split into Cần Thơ City and Hậu Giang province.
Lai Châu province was split into Lai Châu and Điện Biên provinces.
(Vietnam now had 64 provinces and cities.)

2008:
Hà Tây province, Mê Linh district of Vĩnh Phúc province, and four communes of Hoà Bình province were merged into Hanoi.
(Vietnam currently has 63 provinces and cities.)

Cre: Oai Mot