Area Code 289 History:
Area code 289 was put into service. Area code 289 is an overlay of area code 905.
Area code 365 was put into service as an overlay of area codes 905 and 289 on 03/25/2013.
Ten digit dialing (area code + seven digit number) is necessary in the 905/289/365 overlay because two different homes in the same geographic area can have the same seven digit phone number but each would have a different area code.
Major cities or places in Ontario within area code 289 include:
Area codes 905, 289 and 365 cover a portion of southern Ontario including Niagara Falls and the Greater Toronto Area, and the larger communities of Ajax, Ancaster, Aurora, Brampton, Burlington, Caledon, Cobourg, Dunnville, Fort Erie, Georgetown, Hamilton, King Township, Maple, Markham, Milton, Mississauga, Newmarket, Oshawa, Richmond Hill, St. Catharines, Stoney Creek, Thornhill, Unionville, Welland, Woodbridge and many smaller surrounding communities.