I set my first two mystery novels in fictional small towns, one in Alberta and one in Ontario.
These settings have the advantage that you can do whatever you want with the layout of the town and the countryside. The downside is the not inconsiderable work involved in mapping and keeping straight the geography.
Two things changed my mind. The first occurred when I heard an American agent at the Canadian mystery conference Bloody Words. When asked about working with Canadian writers, she said she really wasn't interested in mysteries set in fictional small towns.
In my second novel Body Contact, set in the town of Belleford (fictional) along the Grand River (real), Carl North visits his ex in London, Ontario. It's only a chapter or so, but readers from the London area mentioned how much they appreciated seeing their city in a fictional setting.
Snow Candy was set in St. Thomas (real), and is selling the best of my books so far. One reason is the location. St. Thomas is something like 34,000, Elgin County is 46,000. It's not a huge population, but it has a hell of a lot more book buyers and readers than Belleford (real population: 0).
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