The Ohinemuri County Council first met on 17 November 1885.[1] It was formed from a portion of Thames County.[2] A 1919 petition[3] resulted in loss of the western part of the area[4] to a new Hauraki Plains County in 1920.[5]
The population was 1,516 in 1891,[7] 3,056 in 1945[8] and 5,579 in 1986.[9]
In 1923 Ohinemuri County covered 253 sq mi (660 km2) and had a population of 2,678, with 66 mi (106 km) of gravel roads, 55 mi (89 km) of mud roads and 50 mi (80 km) of tracks.[10]
The 1911 Italianate county offices at 41 Belmont Road, Paeroa, were used by the county until 1986. They are now used by Hauraki Māori Trust Board and protected by an A Category listing in Hauraki District Plan.[11]