"August: __ County": Streep film (5)

I believe the answer is:

osage

(Other definitions for osage that I've seen before include "Language" , "Native Americans from Missouri - age so (anag)" , "Member of the Native American people, once occupying the Missouri valley" , "Age so (anag) - member of a Native American people" , "American Indian" .)

I've seen this clue in the LA Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.