History from ameshistory.org
The town of New Philadelphia (south of the township line) was laid out in 1855 by John Vest. Ely French and L. Reagan of Boonsboro were the surveyors. Jackson Dedrick was believed to be the first person who introduced a stock of goods there. The town maintained only a feeble existence up to the advent of the railroad through the county. When the railroad station was obtained, a new town north of the township line was laid out by the railroad company in January of 1869, and named Ontario. Hiram Scott named the town after his previous home, Ontario, Ohio. Ontario, Iowa, continued to grow and it was not long before it swallowed up the old town of New Philadelphia, which was scarcely a half mile south. The cemetery located just east of North Dakota began as New Philadelphia cemetery.
Ontario was pleasantly situated on the Chicago and North Western Railway, and was surrounded by a most excellent and beautiful portion of country with good settlements. It was on an elevated plain almost completely surrounded by timber. Ontario was ten miles east of Boone, and almost two miles northwest of Iowa State College at Ames. The first buildings of Ontario were two storehouses, erected by Enoch Thurman and brother and Hiram Scott and brother. These structures were destroyed by fire, but others soon took their places. The town improved and built up quickly. The several branches of early business included stores in dry goods and groceries, boots and shoe sales, drugs and medicines, hardware, restaurant, lumber, wagon making, blacksmithing, tailoring, a physician, and hotel. One of the finest depot buildings on the line of the railroad was located there, with H. T. Martin as the agent.
Despite several efforts to incorporate, Ontario was annexed to Ames in 1962.