Grey County is a county of the Canadian province of Ontario. The county seat is in Owen Sound. It is located in the subregion of Southern Ontario named Southwestern Ontario. Grey County is also a part of the Georgian Triangle. At the time of the Canada …Grey County is a county of the Canadian province of Ontario. The county seat is in Owen Sound. It is located in the subregion of Southern Ontario named Southwestern Ontario. Grey County is also a part of the Georgian Triangle. At the time of the Canada 2016 Census the population of the county was 93,830.