The USGA did not disclose a cause of death. He was 82.
Hannigan, who joined the USGA in 1961, was executive director from 1983 to 1988. Among other things, he was responsible for getting Shinnecock Hills back into the U.S. Open rotation in 1986. One of the original five clubs when the USGA was founded in 1895, it had not held a U.S. Open in 90 years.
Hannigan worked as a rules expert for ABC Sports, and later wrote columns for Golf Digest.
USGA executive director Mike Davis said Hannigan's contributions were immense. He said Hannigan's passion left a legacy for the USGA.