What Michigan county northwest of Detroit contains a city that is a northern suburb of Detroit?
Oak Park, Michigan: Oak Park is a city in south Oakland County of the U.S. state of Michigan. Oak Park, Michigan:  It is a northern suburb of the city of Detroit, which is located in neighboring Wayne County, and part of its metropolitan area. Oakland County, Michigan: Oakland County is a county in the U.S. state of Michigan, northwest of the Detroit metropolitan area.
Oakland County