The medical drama primarily takes place in Michigan, at the fictional Lakeshore Sentinel Hospital where each character works.
According to Press & Guide, the series premiere of Good Sam mentions the city of Dearborn in passing. After Sam, her team, and Griff conclude that a patient needs a heart transplant, the vital organ travels via helicopter from an unidentified hospital in Dearborn, and the patient survives.
There have been no further mentions of real-life Michigan cities, but there's a goof noted on IMDb that reads, "In the opening segment [of the pilot], there is snow on cars and parking lot. When the story resumes [six] months later, there is still snow on the ground. Michigan (or Toronto, where it is filmed) does not have six months of winter."
Hopefully, production will fix this if a Season 2 is in the cards!