The Madison Limestone is a thick sequence of mostly carbonate rocks of Mississippian age in the Rocky Mountain and Great Plains areas of the western United States.

[3] Most of the Madison Limestones were deposited during Early to Middle Mississippian time (Tournaisian to Visean stages), about 359 to 326 million years ago.

Older North American usage lists the Madison as being laid down during the Kinderhookian, Osagian, and Meramecian stages.

In the Williston Basin, water was shallow enough for oolite shoals to develop; they later became reservoirs for oil.

[6] The gray cliffs along the Missouri River in the Gates of the Mountains, Montana are formed by Madison Limestone.