Hart Plain is part of Waterlooville and is the northwesternmost ward in the Borough of Havant.^[2] The population of Hart Plain in 2015 was 8,755, making up 7.3% of Havant borough's population.

Hart Plain
Hart Plain Location within Hampshire
Population	9,907 (2011 Census.Ward)[1]
OS grid reference	SU684113
District	Havant
Shire county	Hampshire
Region	South East
Country	England
Sovereign state	United Kingdom
Post town	Waterlooville
Postcode district	PO8
UK Parliament	Meon Valley
List of places UK England Hampshire 50°53′50″N 1°01′44″W / 50.89714°N 1.02876°W / 50.89714; -1.02876

The ward is named after the old Hart Plain House which formerly stood on the site now occupied by Waterlooville Health Centre. The ward consists mainly of post-1950s housing and includes Portsmouth City Council's Wecock Estate.

There is one school in the ward, Hart Plain Junior School, located next to the Cowplain School in Hart Plain Avenue.