John Ignatius Nolan (January 14, 1874 – November 18, 1922) was an American iron molder and politician who represented a Californian district in the United States House of Representatives for five terms from 1913 to 1922. He was elected to a sixth consecutive term but died before the start of the new Congress.

He was succeeded in office by his wife, Mae Nolan.

He was born in San Francisco, California on January 14, 1874. He attended the public schools and worked as an iron molder. An active member of the Union Labor Party,^[1] he was appointed to the San Francisco Board of Supervisors by Mayor P. H. McCarthy in 1911.^[2] He ran for re-election that year, but was narrowly defeated.^[3] In 1912, he was the secretary of the San Francisco Labor Council (he was a member of the Iron Molder's Union).

In 1912, Nolan was elected as a Bull Moose Republican^[4][5] to the 63rd United States Congress.^[6] San Francisco's first labor congressman in eight years, he was a staunch progressive reelected to the four succeeding Congresses. He served from March 4, 1913, until his death. During the 66th United States Congress, he was the chairman of the United States House Committee on Patents, and during the 67th United States Congress, he was the chairman of the United States House Committee on Labor.

He had been re-elected in 1922 to the 68th United States Congress before he died in San Francisco, California on November 18, 1922. He was interred at Holy Cross Cemetery in Colma, California.

After he died, his vacant position in Congress was taken by his wife, Mae Nolan.

• List of United States Congress members who died in office (1900–49)