The most common and most likely answer to this crossword clue is the 7 letter word INDIANA
I've seen this crossword clue in The Sunday Telegraph
I
N
D
I
A
N
A
More clues leading to the result INDIANA
- Popular girl to west of Ohio?
- State — nation not applicable
- State of record company endlessly attracting gossip
- State has popular princess
- Someone from Mumbai, for example, a state
- Charity rejected in tavern, a state
- . Island princess once seen touring northern state
- Restaurant area in US state
- Resident of Punjab
- Country bumpkin ultimately a state
Buddy explains!

The straight part
We know that "part of US" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of us = indiana.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.