The most common and most likely answer to this crossword clue is the 3 letter word EXE
E
X
E
More clues leading to the result EXE
- Former partner on English river
- Unknown character reported in Devon river
- Former partner, say, one running through the West Country?
- Unidentified person on telephone, a West Country banker
- Catch one of former pair in river
- River seen in Sussex, Essex and in Devon!
- In case of earthquake cross river
- River dividing male and female?
- Cross in eastern Spain ‘river of no return’? On the contrary
- River crossing between two points
Buddy explains!

The straight part
We know that "I run through Devon" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i run through devon = exe.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.