 On January 1, 1923, Stolin county (powiat) was created from several gminas within the Łuniniec, Pińsk and Sarny counties.On December 16, 1930, Sarny County was transferred to Wołyń Voivodeship.On April 1, 1935, Kossów county's capital was moved to Iwacewicze and it was renamed as Iwacewicze county.