A lightning ground stroke location system employs a time-of-arrival discrimination scheme which uses, as its time synchronization base, the U.S. Coast Guard LORAN-C navigation network. The system comprises a plurality (at least three and preferably four) of geographically separated lightning stroke monitoring stations. Each station contains a lightning stroke detector and a timing signal generator that is synchronized with the timing signal generator at each other respective detection location. The timing signal generation equipment at each receiver is comprised of a LORAN-C signalling responsive receiver which monitors the same encoded signal group emitted from a common LORAN-C reverence source. Each of the ground stroke detection stations is further connected via a respective communication link to a central processing facility.When a ground stroke occurs, the electromagnetic pulse emitted is detected by each listening station, which records the time of detection of the ground stroke by sampling an internal synchronized clock at that particular station so as to record the time that the stroke was detected relative to the standard timing cycle is emitted by the reference Coast Guard station source. This time data is then transmitted to the central processing station, which after compensating for relative LORAN time signal propagation delay calculates the stroke location.