The county gradually shrunk in size as the city of Auckland grew, and suburban areas became boroughs.

It was replaced in 1849 by Governor William Hobson with a system of Hundreds, and reinstated in 1876.

[2] The county did not administer the area in the way local government does, instead was primarily used as a way to order land division and sales.

[citation needed] These boroughs were joined by Mount Eden in 1906,[1]: 52  Avondale in 1922, One Tree Hill in 1930 and Ellerslie in 1938.

[3] With the local government reforms of 1989, all of the former territory of the county was incorporated into Auckland City.