Letters regularly dispatched from US to African capital (5)
I believe the answer is:
sofia
'capital' is the definition.
(capital of Bulgaria)
'letters regularly dispatched from us to african' is the wordplay.
I cannot really understand how this works, but
'from' could be 'of' (I've seen this in other clues) and 'of' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sofia that I've seen before include "Capital of Bulgaria" , "Bulgarian capital" , "European city" , "capital city" , "Foreign city" .)