The most common and most likely answer to this crossword clue is the 8 letter word COTTAGES
I've seen this crossword clue in The Daily Telegraph
C
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More clues leading to the result COTTAGES
Buddy explains!

The straight part
We know that "country residences" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case country residences = cottages.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.
What does COTTAGES mean?
COTTAGES noun- A small house.
- A seasonal home of any size or stature, a recreational home or a home in a remote location.
- A public lavatory.
- A meeting place for homosexual men.
- To stay at a seasonal home, to go cottaging.
- (of men) To have homosexual sex in a public lavatory; to practice cottaging.