Kolno County is a unit of territorial administration and local government (powiat) in Podlaskie Voivodeship, north-eastern Poland. It came into being on January 1, 1999, as a result of the Polish local government reforms passed in 1998. Its administrative seat and largest town is Kolno, which lies 89 km west of the regional capital Białystok. The only other town in the county is Stawiski, lying 16 km east of Kolno. The county covers an area of 939.73 km2. As of 2019 its total population is 38,249, out of which the population of Kolno is 10,214, that of Stawiski is 2,174, and the rural population is 25,861.

Neighbouring counties

Kolno County is bordered by Pisz County to the north, Grajewo County to the north-east, Łomża County to the south and Ostrołęka County to the west.

Administrative division

The county is subdivided into six gminas (one urban, one urban-rural and four rural). These are listed in the following table, in descending order of population.