Information about the Middle Patuxent Environmental Area and the Middle Patuxent Environmental Foundation. The MPEA is owned by Howard County, Department of Recreation and Parks. The MPEF provides financial support to Howard County for the preservation and maintenance of the MPEA. Middle Patuxent River runs through the MPEA on its way to the Chesapeake Bay. Access to the MPEA is available from Trotter Road in Columbia, Maryland, or from Clarksville, Maryland.