Biaà Âystok County () is a unit of territorial administration and local government (powiat) in Podlaskie Voivodeship, north-eastern Poland, on the border with Belarus. It was created on 1 January 1999 as a result of the Polish local government reforms passed in 1998. Its administrative seat is the city of Biaà Âystok, although the city is not part of the county (it constitutes a separate city county).
The county contains nine towns: à Âapy, south-west of Biaà Âystok, Czarna Biaà Âostocka, north of Biaà Âystok, Wasilków, north of Biaà Âystok, Choroszcz, west of Biaà Âystok, Supraà Âl, north-east of Biaà Âystok, Michaà Âowo, east of Biaà Âystok, Zabà Âudów, south-east of Biaà Âystok, Tykocin, west of Biaà Âystok, and Suraà ¼, south-west of Biaà Âystok.
The county covers an area of , making it the largest county in Poland (ahead of Olsztyn County). As of 2019 its total population is 148,745, out of which the population of à Âapy is 15,609, that of Czarna Biaà Âostocka is 9,318, that of Wasilków is 11,527, that of Choroszcz is 5,890, that of Supraà Âl is 4,605, that of Michaà Âowo is 3,026, that of Zabà Âudów is 2,462, that of Tykocin is 1,973, that of Suraà ¼ is 988, and the rural population is 93,347.
Apart from the city of Biaà Âystok, Biaà Âystok County is bordered by Hajnówka County and Bielsk County to the south, Wysokie Mazowieckie County, Zambrów County and à Âomà ¼a County to the west, Moà Âki County to the north-west, and Sokóà Âka County to the north-east. It also borders Belarus to the east.
The county is subdivided into 15 gminas (nine urban-rural and six rural). These are listed in the following table, in descending order of population.