the main area code, 519, was created in 1953 from the western portion of 416 and the southwestern portion of 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 dialling became mandatory. area code 548 was added as a third overlay beginning on june 4, 2015. area code 382 has been reserved as a fourth code for the region.