1770 – February 16, 1820) was an American hunter and fur trapper in the Pacific Northwest, including present-day Oregon, Washington, Idaho, Western Montana and Southern British Columbia.
John Day was born around 1770 in Culpeper County, Virginia and came west through Kentucky to Spanish Upper Louisiana (now Missouri) by 1797.
After a few years trading up the Missouri River, in late 1810 he was engaged as a hunter for the Pacific Fur Company and joined an overland expedition led by Wilson Price Hunt.
After finally making their way to Fort Astoria in April 1812, Day was assigned to accompany Robert Stuart back east to St. Louis in June 1812, but was left on the Lower Columbia River where he is said to have gone mad.
John Day died February 16, 1820, at the winter camp of Donald MacKenzie's Snake Country Expedition in what is now the Little Lost River valley in Butte County, Idaho.