Park Drive is a mostly one-way, two-lane parkway in the Fenway-Kenmore neighborhood of Boston that runs along the northern and western edges of the Back Bay Fens before ending at Mountfort Street. As part of the Emerald Necklace park system mainly designed by Frederick Law Olmsted in the late 19th century, Park Drive, along with the Back Bay Fens and the Fenway, connects the Commonwealth Avenue Mall and Boylston Street to Beacon Street and the Riverway. For a portion of its length, the parkway runs along the Muddy River and is part of the Metropolitan Park System of Greater Boston's Muddy River Reservation. Like others in the park system, it is maintained by the Massachusetts Department of Conservation and Recreation.