the 233 camping sites at the south rim of the grand canyon sell out for easter every year , no matter how early easter is , according to morrow . ; the park service keeps precise annual records of visitors to the 355 areas under its supervision -- parks , monuments , historic sites , seashores. ; ken e. hornback of the service 's socioeconomic studies section in denver said that attendance at some was at saturation now , citing yosemite , the grand canyon and golden gate national recreation area near san francisco . ;