18 Pa. C.S. § 5502 : Consolidated Statutes — CRIMES AND OFFENSES — DEFINITION OF SPECIFIC OFFENSES — OFFENSES AGAINST PUBLIC ORDER AND DECENCY — RIOT, DISORDERLY CONDUCT AND RELATED OFFENSES — DEFINITION OF OFFENSES GENERALLY — Failure of disorderly persons to disperse upon official order

Where three or more persons are participating in a course of disorderly conduct which causes or may reasonably be expected to cause substantial harm or serious inconvenience, annoyance or alarm, a peace officer or other public servant engaged in executing or enforcing the law may order the participants and others in the immediate vicinity to disperse. A person who refuses or knowingly fails to obey such an order commits a misdemeanor of the second degree.