Unitization agreement maps identify areas of land that parties with interests therein are bound, by agreement, to share investment costs and revenues generated from the production of minerals within the defined boundary. A unit may be created by convention or by order of a state or federal government agency. A unit formed by order of government is called a 'compulsory unit.'

Detroit River units have been named as such because a majority of the minerals produced within them originated in a rock formation called the Detroit River group, which contains a variety of rock types, including shale, gypsum, and limestone.

To view a map, select a county from the State map or list

Pause the pointer over a county on the state map to view the county name.