Southern England located in/on physical feature England
Definitions
For official purposes, the UK government does not refer to Southern England as a single entity, but the Office for National Statistics divides UK into twelve regions. In England, the North West, North East and Yorkshire and the Humber make up the North ("centre-north"); the West Midlands and East Midlands (as well as Wales) make up the Midlands ("centre-south") and the rest of England make up the South.Culturally speaking, the majority of people think that the South consists of the South East (92%), Greater London (88%), South West (87%),  and to lesser extent the East of England (57%). However, 35% of people surveyed placed the East of England as part of the Midlands. Generally people in the North tend to put the East of England in the South more than people in the South or Midlands.
situated in/on physical feature positioned in/on physical feature found in/on physical feature placed in/on physical feature situated on/at physical feature