June 11, 1883, William Morfitt, James W. Virtue, Daniel Smith and Mary Richardson formed a new town site just south of confluence of the Malheur and Snake rivers, with the knowledge that the railroad would be coming soon, and the hope that their investment would pay off handsomely.

Naming the town was difficult for the founders. Morfitt wanted it to be named Ione (another city in Oregon, by the way), after his only daughter, and Virtue wanted it named after his birthplace in Canada. Local legends cite both h the flipping of a coin and a random drawing from a hat as the method of solving the dilemma, but regardless of the actual method, Ontario was the name selected.

The town was incorporated in 1896, and E.H. Test was its first mayor. During Test's administration, the first jail was built for $100. July 16, 1896, the city council instructed the city marshal to collect $7.50 a month from prostitutes, and deposit the money in the city's coffers.

Today, Ontario is a largely agricultural community of around 10,000.  Crops include onions, russet potatoes, sugar beets and peppermint. The people in this part of Oregon have diverse cultural backgrounds, such as Japanese, Basque, Mexican, American Indian and European.  It is also the home of the Snake River Correctional Facility, one of the largest prisons in Oregon.