The Department of Environmental Quality approved West Bay Exploration Co.'s application Thursday.
Adam Wygant of the Office of Oil, Gas and Minerals said the DEQ took twice as long as usual to review the application because of public concerns.
The DEQ says the location of the well is zoned agricultural and there are no structures, residences or water wells within 600 feet.
Scio Township, Ann Arbor and Washtenaw County commissioners have passed resolutions against drilling in the area. The Michigan League of Conservation Voters claims state policy is stacked in favor of drilling.