It was formerly Buckingham County, one of the 18 counties of Tasmania and one of the first eleven proclaimed in 1836 and is bordered to the north by the River Derwent, and to the south by the Huon River.

An earlier Buckingham County existed from 24 September 1804 until 1813 as an administrative division whilst Van Diemen's Land was administered as two units.

It was defined as all of Van Diemen's Land south of the 42nd parallel (between Trial Harbour and Friendly Beaches, and governed by David Collins.

Cornwall County occupied the remainder of the island.

[1][2] On 15 January 1836 George Arthur, the Lieutenant Governor of the Island of Van Diemen's Land proclaimed, via The Hobart Town Courier, the first counties and parishes to be surveyed in the colony.