Kielce Voivodeship
In the Second Polish Republic, Opoczno County was part of Kielce Voivodeship (1919–39). On April 1, 1939, the county was moved to Lodz Voivodeship. During World War II, Opoczno County was disbanded and merged into District (Kreis) of Tomaszow Mazowiecki. After the war, in 1944 – 1950, Opoczno County belonged to Lodz Voivodeship. On July 1, 1950, it was moved to Kielce Voivodeship.