That isn't exactly clear, and the last of them lived on Alaska's remote St. Paul Island, I believe once a part of the Bearing Land Bridge, at least as late as 5600ya, and some may have survived on the Aleutian Islands as late as 1650BC, and possibly, though unlikely, even as late as 800AD. The last ones were not hunted.
FWIW I believe you're talking about Mammoths, not Mastodons. Similar but not same animal. Mastodons are believed to have gone totally extinct around 10,000 years ago.
There's so much evidence of human hunting of Mastodons, and the timelines are co-related so highly, it's hard to believe we weren't involved heavily in their extinction even if there were other (climate/habitat) related factors.
That isn't exactly clear, and the last of them lived on Alaska's remote St. Paul Island, I believe once a part of the Bearing Land Bridge, at least as late as 5600ya, and some may have survived on the Aleutian Islands as late as 1650BC, and possibly, though unlikely, even as late as 800AD. The last ones were not hunted.