It was established on January 1, 1999, as a result of the Polish local government reforms passed in 1998.

The only towns in Biała Podlaska County are Międzyrzec Podlaski, which lies 24 km (15 mi) west of Biała Podlaska, and the border town of Terespol, 32 km (20 mi) east of Biała Podlaska.

The county covers an area of 2,753.67 square kilometres (1,063.2 sq mi).

The county is subdivided into 19 municipalities (two urban and 17 rural).

These are listed in the following table, in descending order of population.