Song Be province was merged from which localities?

Song Ba province was established on July 2, 1976 on the basis of merging 2 localities when they were first established. Song Ba province has 14 districts.

1996

On November 6, 1996, the 10th Session of the 9th National Assembly passed a resolution to divide Song Be province to re-establish Binh Duong and Binh Phuoc provinces.
Accordingly, Binh Duong province includes Thu Dau Mot town and 3 districts: Ben Cat, Tan Uyen, Thuan An (now includes 5 cities: Thu Dau Mot, Di An, Thuan An, Tan Uyen, Ben Cat and 4 districts: Bau Bang, Bac Tan Uyen, Phu Giao, Dau Tieng). The provincial capital is located in Thu Dau Mot town.
Binh Phuoc province consists of 5 districts: Binh Long, Bu Dang, Dong Phu, Loc Ninh, Phuoc Long (today includes Dong Xoai city, 3 towns: Binh Long, Phuoc Long, Chon Thanh and 8 districts: Bu Dang, Bu Dop, Bu Gia Map, Dong Phu, Hon Quan, Loc Ninh, Phu Rieng). The provincial capital is located in Dong Xoai city.

Source: https://vtcnews.vn/tinh-song-be-duoc-hop-nhat-tu-nhung-dia-phuong-nao-ar929570.html