If the ticket you received says “U.S. District Court Violation Notice” across the top, then you received a federal ticket. Federal tickets are issued by law enforcement personnel from agencies such as the U.S. Park Police, U.S. Fish & Wildlife, Department of Defense Police, U.S. Coast Guard, U.S. Provost Marshal, Airforce, Marines & Navy Security Forces, U.S. Postal Police, U.S. Customs, U.S. Border Patrol, and V.A. Police.
This site allows online payments of federal tickets only, not tickets issued by state or local jurisdictions.