The area codes 204 and 431 belong to part of North America as well as the Province of Manitoba in Canada. The 204 area code was originally put into use when the first area codes were assigned on January 1, 1947. There were 86 of them for the continental US and for nine of Canada’s provinces.
The area code was used up until 2012. In 2009 the Canadian Numbering Administrator predicted that the code would become exhausted in a few years despite all of Manitoba only having a population of over a million people. This was when the new area code 431 was developed.
The other issue was the allocation scheme used to allow 10,000 numbers in a central prefix to just local telephone carriers. Once these numbers were used they could not be reassigned. If a rate locale had more than enough numbers using the 204 area code, those numbers still could not be used anywhere else in Canada. So, it became necessary to come up with a new area code particularly one that would handle all the cell phones and device numbers populating larger cities like Winnipeg.
The number was put into place in November 2012 and shortly before then 10-digit dialing became mandatory in Manitoba by the Canadian Radio-Television and Telecommunications Commission. This kept rural Manitobans from having to go through the expense and inconvenience of changing their numbers. It also kept the province from holding one area to the 204 number and another to receive 431.
Currently, major places that have the 204 number include Portage la Prairie, Selkirk, Steinbach, Swan River, and Winnipeg and the rest of Manitoba. Winnipeg is the capital of the province of Manitoba and is probably the largest area for the area code 204. It is set between The Forks, a historic site near the Red and Assiniboine rivers.