The town lies on the River Itchen, one of England's premier chalk streams for fly fishing, and a designated site of Special Scientific Interest.

The modern town of Eastleigh lies on the old Roman road, built in A.D.79 between Winchester (Venta Belgarum) and Bitterne (Clausentum).

[10] There is additional evidence of this settlement in a survey from the time which details land in North Stoneham being granted by King Æthelstan to his military aid, Alfred in 932 AD.

Eastleigh has seen a rapid and controlled expansion in residential, industrial and commercial development over recent years.

[15] The United States Navy established a naval air station on 23 July 1918 to assemble and repair Caproni Ca.5 and Airco DH.4 and DH.9 bombers for the Northern Bombing Group of the First World War.

Eastleigh Museum, which is to be found in the High Street, holds information about the town and the surrounding villages, including Bishopstoke which had been the largest residential area.

[21] Adjacent to the main church building is the Wells Place Centre, built on the site of a former dairy which itself replaced a bacon factory.

They are coached by Matt Guymon and play home games at the Fleming Park Leisure Centre.

They currently have four senior sides, colts and young player development, their 1st XV currently play in the London 2 South West.

The club is primarily based at Places Leisure, Eastleigh and also provides lessons and training at Oaklands Pool in Southampton.

Eastleigh has a tradition of close contests, and Huhne narrowly beat the Conservative candidate Conor Burns with the second lowest swing against the Liberal Democrats of any seat with a retiring MP (2.6%).

Chris Huhne was appointed as Secretary of State for Energy and Climate Change following the 2010 general election.

Huhne resigned the seat in February 2013 after pleading guilty to perverting the course of justice over a 2003 speeding case.

On 1 April 2021 the town of Eastleigh became a civil parish, having previously been an unparished area within the borough.

The Swan Centre included a French-style café and a new library[34] (replacing the former library situated in the Park, now used as part of The Point) Famous people linked to Eastleigh include the painter Mary Beale, Chrystabel Leighton-Porter, the model for the Second World War cartoon character Jane,[35] and Benny Hill who both lived in the town.

His time working in Eastleigh on a horse-drawn milk float gave him his inspiration for his hit record, Ernie, The Fastest Milkman In The West.

Sporting notables include Tommy Green who won an Olympic Gold Medal at the 1932 Los Angeles Games in the 50K walk, and Vince Hawkins who was British Middleweight Boxing Champion in the late 1940s.