The Night Train drug seizure was a December 1977 seizure of 54 tons of marijuana by the United States Coast Guard off the southeastern coast of Florida which marked the beginning of Operation Stopgap, a United States federal law enforcement inter-agency drug interdiction operation focusing on interdicting drugs from Colombian cartels and other illicit Central and South American drug sources. The Night Train seizure was the largest single drug seizure in history at the time it occurred, and it remains one of the largest marijuana seizures made in the territorial waters of the United States.