The administrative centre was the village of Gjerpen, which is now part of the growing town of Skien.

On 1 January 1856, an area of Gjerpen Municipality (population: 1,286) was annexed by the growing town of Skien.

On 1 January 1903, an unpopulated area of Saude Municipality was transferred to Gjerpen.

Again, on 1 July 1916, another area of Gjerpen Municipality (population: 1,332) was annexed by the growing town of Skien.

Then on 1 July 1920, an area of southern Gjerpen (population: 437) was transferred to the town of Porsgrunn.

The former manor house is now operated as an auction facility (Nye Store Mæla Gård Auktion).