Former president's welcome concerning East Midlands area (12)
I believe the answer is:
lincolnshire
'east midlands area' is the definition.
The definition suggests a singular noun which matches the answer.
'former president's welcome concerning' is the wordplay.
'former president's' becomes 'Lincoln's' (Abraham (Abe) Lincoln).
'welcome' becomes 'hi' (both are greetings).
'concerning' becomes 're' (both can mean on a particular topic).
'lincolns'+'hi'+'re'='LINCOLNSHIRE'
Can you help me to learn more?
(Other definitions for lincolnshire that I've seen before include "English county" , "County (with horse race and poacher)" .)