Oakville is a town in Halton Region, Ontario, Canada. It is located on Lake Ontario between Toronto and Hamilton. It is Ontario's largest town. Oakville is part of the Greater Toronto Area, one of the most densely populated areas of Canada.

Odessa, originally named Millcreek, was renamed in 1855 by its postmaster to commemorate the 1854 British siege of the Black Sea port at Odesa in Ukraine during the Crimean War.

Ohsweken, is a village on the Six Nations of the Grand River First Nation Indian reserve near Brantford, Ontario.

A southwest Ontario Community near Windsor, located on Highway #3, and close to the 401 Highway, which is just north of the community.

The Township of Oliver Paipoonge is located strategically at the Head of the Great Lakes, near the geographical center of North America, just 20 kilometres west of Thunder Bay.

Located in Victoria County.

An unincorporated community in North Frontenac Township, County of Frontenac.

Part of the Greater Sudbury area.

Community in central Ontario that covers a land area of 61,000 hectares, from the northern border of Barrie and Lake Simcoe south to Orillia and north to Tay and Severn Townships.

An unincorporated Simcoe County community.

A Wellington County hamlet located northeast of Guelph.

Otonabee–South Monaghan, a township in central-eastern Ontario, Canada, in Peterborough County.

Ottawa is Canada's capital city. On January 1, 2001, the 11 municipalities which made up the Region of Ottawa-Carleton joined together to create the new City of Ottawa. The former municipalities are the cities of Ottawa, Gloucester, Cumberland, Nepean, Kanata, Vanier, Rockcliffe Park, and the townships of West Carleton, Rideau, Goulbourn, Osgoode.

Otterville is a village in Norwich Township in Oxford County, Ontario, Canada.