John Day is a city located about 2 miles (3.2 km) north of Canyon City in Grant County, Oregon, at the intersection of U.S. Routes 26 and 395. The city was named for the nearby John Day River, which had been named for a Virginian member of the 1811 Astor Expedition, John Day. The city was incorporated in 1901.
As of the 2010 census, the city had a total population of 1,744, making it the largest city in the county.