John Patrick Hartigan (December 29, 1887 – August 10, 1968) was Attorney General of Rhode Island, a United States district judge of the United States District Court for the District of Rhode Island and a United States Circuit Judge of the United States Court of Appeals for the First Circuit.

[4] He was in the United States Army as a Second Lieutenant during World War I from 1917 to 1918 in the 304th Infantry Regiment.

[6] Hartigan was nominated by President Franklin D. Roosevelt on January 11, 1940, to a seat on the United States District Court for the District of Rhode Island vacated by Judge John Christopher Mahoney.

His service was terminated on January 13, 1951, due to his elevation to the First Circuit.

[8] Hartigan was nominated by President Harry S. Truman on December 21, 1950, to a seat on the United States Court of Appeals for the First Circuit vacated by Judge John Christopher Mahoney.