The 1851 census defined a South Midland division which comprised Middlesex (except the Metropolitan portion), Hertfordshire, Buckinghamshire, Oxfordshire, Northamptonshire, Huntingdonshire, Bedfordshire and Cambridgeshire.

[1] To understand why the South Midland division extends so far south, it may help to know that some 19th-century geographers defined a Central Plain consisting of the middle parts of England, lying between the valleys of the River Trent and the River Thames to the north and south, and between the Fen district and the high ground bordering the valley of the River Severn to the east and west.

[3] The main settlements are Aylesbury, Milton Keynes, Northampton, Corby, Kettering, Wellingborough, Rushden, Bedford and Luton.

A report in 2002 found that: "The most successful economies are those of Milton Keynes and Northampton.

"[4] The region is served by London Luton Airport (the fifth busiest airport in the United Kingdom), and has important road and rail links, being served by the M1 motorway and both the West Coast and East Coast main lines, connecting it with London, Birmingham and the north of England.