The Unites States have a far simpler system. Each airport has an IATA (International Air Transport Association) 3-letter code, which you will see on your luggage label. The Americans simply add a 'K' to the IATA code to produce the ICAO code eg MCO (Orlando) becomes KMCO. Simple!
You would think Canada's system of adding C to the IATA code would be simple too, except for historical reasons, mainly to do with weather stations, we have names like CYYR, CYYT, CYYC, CYYZ, etc.
The only airfield in this sequence which is not a major airport, is CYYM - Cowley Alberta. A grass strip, nowadays used only for glider wave-flying, but originally was an emergency landing ground for TCA's Lockheed Electras, if bad weather precluded a flight westwards through the Rockies.