Gayle and I saw the Common Moorhen at 2:30 PM today in about the same place it was yesterday.  It was along the first island to the east of the rope that keeps boaters from going into the "wildlife area".    It was along the south side of the island, and about 75 feet from the east tip of the island.  Occasionally it got in dense vegetation were you couldn't see it but it didn't stay there long.   Hopefully this map will help orientate you.

http://www.howardbirds.org/birdinghowardcounty/Centennial/centennial_directions.htm

Bill Hill
Glenwood, Md.