The most common and most likely answer to this crossword clue is the 8 letter word COUNTIES
C
O
U
N
T
I
E
S
Buddy explains!

The straight part
We know that "administrative areas" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case administrative areas = counties.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 COUNTIES mean?
COUNTIES noun- The land ruled by a count or a countess.
- An administrative region of various countries, including Bhutan, Canada, China, Croatia, Ireland, Japan, New Zealand, Norway, Poland, Romania, South Korea, Sweden, the United Kingdom, and 48 of the 50 United States (excluding Alaska and Louisiana).
- A definitive geographic region, without direct administrative functions.
- A jail operated by a county government.