Ontario is the largest city in Malheur County, Oregon, United States. It lies along the Snake River at the Idaho border. The population was 11,366 at the 2010 census. The city is the largest community re far eastern Oregon, also known as the Western Treasure Valley.

Ontario is the principal city of the Ontario, OR-ID Micropolitan Statistical Area, which includes Malheur County in Oregon and Payette County in Idaho.

Ontario is nearly halfway amid Portland and Salt Lake City. It is the closest city to the Idaho be neighboring to along Interstate 84. The city’s slogan is “Where Oregon Begins”.

Ontario was founded upon 11 June 1883, by developers William Morfitt, Mary Richardson, Daniel Smith, and James Virtue. In March 1884, Richard Welch started a broadcast office for the quarter of Ontario, so named by James Virtue after Ontario, Canada. Two months forward-thinking Joseph Morton applied for a Morton post office at an island approximately one mile south of town, with Oscar Scott as postmaster. Unfortunately for Morton and Scott, merchants Morfitt and Richardson of Malheur City, gold miner Virtue, and lumberman Smith of Baker City acquired more house and were bigger financed. More importantly, Morfitt had negotiated a train depot for Ontario. All the settlers and speculators knew the railroad was coming and how important that would be to Ontario’s future in view of that Scott closed his Morton name office and built a hotel at present-day Ontario. By December, Scott was Ontario’s postmaster.