Ontario moved to multi-year, renewable plates for the first time in 1973. The alphabetic series of the time were allocated throughout the province as shown in the table below. You can sort by any column, or search for a city name.

Ontario intended for the 1973 series plates to last for five years before withdrawing them in favour of a completely new series, as is common practice among many other provinces and US states. However, a decision was made to simply continue the 1973 series. This means that any plate issued in 1973 can theoretically still be legally used on the road. Once the end of an alphabetic series is reached, it is either flipped, or a new one is started.