Montana's __ National Park (7)

I believe the answer is:

glacier

(Other definitions for glacier that I've seen before include "Slowly moving mass of ice" , "Moving body of ice" , "One creeps downhill" , "Large flow of ice" , "one goes slowly downhill" .)

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.