The first automated toll-free numbers were assigned with area code 800, created as inbound Wide Area Telephone Service (InWATS) in 1966 (U.S. intrastate) and 1967 (interstate).
Originally, 800-services were isolated between the US and Canada, but in 1984, an agreement between carriers in the two countries allowed the numbers in each country to be accessible to the other; providers of 800 service were able to add zones to cover the expanded areas able to be offered.