Kongsberg is a town and municipality in Buskerud county, Norway. The city was founded in 1624 under the name Konings Bierg by Danish-Norwegian king Christian IV as a mining community. In Norway’s 1749 census, Kongsberg was the most populous town in Eastern Norway. It was granted its royal charter of trade—amounting to official township—in 1802. The municipality of Kongsberg was established on 1 January 1838 (see formannskapsdistrikt). The rural municipalities of Ytre Sandsvær and Øvre Sandsvær were merged into the municipality of Kongsberg on 1 January 1964.