Prince George's County Updates

A few new items for Prince George's County:

• Campus Recreational Services at the University of Maryland - College Park uses 452.3500 [ d466] (R).
• Six Flags America uses 468.9625 [ d261] for shows/concerts. 468.6250 [192.8] may be for special events. And 461.4125 [ d261] (R) is used for ride statuses, but also may be general guest services.