Area coe 519 is an area code that covers almost all of southwestern Ontario and was introduced in 1953; portions of area code 416 and area code 613 were combined to form the new code area. In turn, in 1957, parts of 519 and 613 formed 705. It is bounded by area code 905 in the east except for Simcoe County which is bordered by area code 705 in the northeast. 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).