It appears to be the proof silver version of a medal struck by Northwest Territorial Mint; they also struck the piece in nickel, bronze and something they call MerlinGoldĀ®.
I say "appears to be" because the overall design of your piece is a close match to the NWT Mint piece as depicted on their site, but I do notice a few small differences in the details.
I would contact NWT Mint and send them the images of your piece and ask them to confirm if it is one of theirs.
Here's a link to a page with all of the medal versions listed:
https://store.nwtmint.com/Historical/Tribute/1Good luck!