This includes[clarification needed] the Chiltern Main Line, which also runs in the same area between the two cities. The route taken by the railway line closely follows the motorway except for the central section where the railway does not serve Oxford. Unlike the motorway, the Chiltern Main Line stretches deep into both London and Birmingham.
The area followed by the M40 includes southern Buckinghamshire, eastern Oxfordshire and central/southern Warwickshire. Despite serving London and Birmingham, the M40 does not enter either cites, instead other roads/motorways continue onwards (e.g. the A40 continues right into central London). The motorway runs between and .
Both rail and road now travel sharply to the north west, serving Warwickshire.
Main towns/cities served
The following table only includes places situated near the motorway and those close enough to be considered[by whom?] 'near the motorway' (like Aylesbury). Other places that may use the motorway (for access to the north) are not included as they have other motorway access (for example Slough). Small villages are not included. Population figures are based on the 2001 census by the Office for National Statistics 
|Place||Population||Ceremonial County||Main Railway station||Motorway junction|
|Gerrards Cross/Chalfont St Peter||19,622||Buckinghamshire||Gerrards Cross||1|
|High Wycombe Urban Area||118,229||Buckinghamshire||High Wycombe||3,4|
|Thame||10,886||Oxfordshire||Haddenham and Thame Parkway||7|
|Aylesbury Urban Area||69,021||Buckinghamshire||Aylesbury||8A,9|
|Leamington Spa||45,114||Warwickshire||Leamington Spa||15|
George Wimpey, RAF Air Command, Hyundai UK, Dreams, the UK base of Ariston (now owned by Indesit) and the UK headquarters of Staples are based in High Wycombe. The UK base of Robert Bosch is in Denham, near Gerrards Cross. Pioneer UK is in Stoke Poges and the Barracuda Group (owner of Varsity) is in Marlow, both locations being near the motorway.
Stratford-upon-Avon is world-famous as Shakespeare's hometown and so tourism is a major industry. The NFU Mutual Insurance Company is also based in the town. ConocoPhillips, JET (petrol), BMW, and Volvo Group are based in Warwick.
- "Archived copy". Archived from the original on 21 November 2008. Retrieved 31 July 2008.CS1 maint: Archived copy as title (link) In Buckinghamshire
- "Archived copy". Archived from the original on 9 October 2008. Retrieved 31 July 2008.CS1 maint: Archived copy as title (link) Stokenchurch to Waterstock
- "Archived copy". Archived from the original on 9 October 2008. Retrieved 31 July 2008.CS1 maint: Archived copy as title (link) Waterstock to Umberslade