The legendary Ernest Hemingway home appears doomed ... an almost certain casualty of Hurricane Irma ... this according to local law enforcement.

The Key West home -- made of wood and built in the 1850's -- sits about 16 feet above sea level, which is the highest point on the island. Law enforcement tells us they're expecting at least 15 feet of water to flood the area ... so the outcome is bleak.

The Hemingway Home's manager, 72-year-old Jacqui Sands, has already said she's staying put to maintain the home and its 55 or so roaming cats. Jacqui and some staff are boarding up and bunkering down.

If Jacqui or her staff are injured, cops say they'll be left to fend for themselves, because hospitals, ERs, rescue crews and other government assistance will not be available.

A farewell to Hemingway?