I'm assuming you're asking about current clubs in Northern Ontario -- these would be Timmins, Sudbury, Iron Bridge (Northern Ontario Retriever Association), Sault Ste. Marie(Algoma) as well there is a FT near to Sarnia at South Western Ontario Trial. Check out the website for the National Retriever Club of Canada for the complete listing of all FTs in Canada -- might be some close trials in Manitoba as well.
Here is a place to start www.nrcc-canada.com There are alot of clubs in Ontario, but only a few in the prarie provinces. Manitoba gun dog Association & Winnipeg field trial club are my local clubs and reasonalbly close to you.