Starting 1 June 1975, pursuant to a law proclaimed on 28 May 1975, the Białystok Voivodeship was formed from part of the existing Białystok Voivodeship. In addition the intermediate administrative level of powiats were eliminated, but the secondary administrative units of gminas were retained. The unstated reason for the 1975 reform was the desire of the Polish Central Committee to strengthen control over lower layers of the state apparatus. After Edward Gierek replaced Władysław Gomułka as first secretary of the Polish United Workers' Party, his clique maintained power by dividing the Politburo. Through administrative reorganization and the new territorial division, Gierek was able to nominate his supporters to provincial committees and break the hold of older elements of the party. After the fall of the People's Republic of Poland, District Offices were established in the voivodeship under the Act of 22 March 1990 and the Regulation of the Minister – Head of the Office of the Council of Ministers on 1 August 1990. Within the limits of the district offices were several gmina. The offices did not constitute organs of self-government, but performed the tasks and powers of the voivodeship administration. During 1991 and 1992 the large municipalities were restructured, significantly changing the division of powers between the voivodeship cities and the surrounding rural gminas. In the Polish administrative reform of 1999 Poland introduced a further reform of local government administration, disestablishing the Białystok Voivodeship effective 31 December 1998 and establishing the Podlaskie Voivodeship.
Administrative divisions
From 1975 until 1990 the voivodeship was solely divided into Gmina of the following types:
In 1990 the Voivodeship set up a number of District offices :
Białystok for the gminas of: Choroszcz, Czarna Białostocka, Dobrzyniewo Kościelne, Gródek, Juchnowiec Dolny, Łapy, Michałowo, Poświętne, Supraśl, Suraż, Turośń Kościelna, Tykocin, Wasilków and Zabłudów along with the City of Białystok
Bielsk Podlaski for the gminas of: Bielsk Podlaski, Boćki, Brańsk, Orla, Rudka and Wyszki along with the Cities of Bielsk Podlaski and Brańsk
Hajnówka for the gminas of: Białowieża, Czeremcha, Czyże, Dubicze Cerkiewne, Hajnówka, Kleszczele, Narew and Narewka along with the City of Hajnówka
Mońki for the Gminas: Jasionówka, Jaświły, Knyszyn, Krypno and Mońki
Siemiatycze for the gminas of: Drohiczyn, Dziadkowice, Grodzisk, Mielnik, Milejczyce, Nurzec-Stacja and Siemiatycze along with the City of Siemiatycze
Sokółka for the gminas of: Dąbrowa Białostocka, Janów, Korycin, Krynki, Kuźnica, Nowy Dwór, Sidra, Sokółka, Suchowola and Szudziałowo
