519 is the telephone area code which covers most of southwestern Ontario and was introduced in 1953 from portions of area codes 416 and 613. In 1957, parts of 519 and 613 formed 705. It is mostly bounded by area code 905, except for Simcoe County which is bordered by 705. It was overlaid with the new area code 226 on October 21, 2006, at which time ten-digit dialing became mandatory. Area code 226 is Canada's 25th geographical area code (not including area code 600).
The primary ILEC (Incumbent Local Exchange Carrier) in 519/226 is Bell Canada, with numerous other small independent companies that covered vast tracts of rural Ontario. Since competition for service was mandated in 1997, numerous CLECs (Competitive Local Exchange Carrier) have also started serving the region.