Patrick S. Nagle was an American political organizer who served as the U.S. Marshal for Oklahoma Territory between 1896 and 1897. During the 1890s, he was a prominent Democratic Party organizer. After 1908, he joined the Socialist Party of Oklahoma as an organizer.

Nagle's parents, George Nagle and Mary Burke immigrated to the United States in the 1830s from Ireland, eventually settling in Indiana. Patrick S. Nagle was born on November 23, 1858, and grew up in a family of Roman Catholics and Jacksonian Democrats. He moved to Kansas with his family in 1876. He was later elected to county office, admitted to the Kansas Bar Association, and participated in the Land Run of 1889, eventually settling in Kingfisher, Oklahoma. He married Angie McCartney on September 10, 1894.^[1]

Nagle was a leading figure in Oklahoma Territory's Democratic Party, specifically within the conservative wing that backed Grover Cleveland.^[1] He served as the U.S. Marshal for Oklahoma Territory from February 18, 1896, to October 25, 1897.^[2] In 1908, he joined the Socialist Party of Oklahoma and, according to the Encyclopedia of Oklahoma History and Culture, was both respected for his leadership, and "resented" for "his dictatorial methods."^[1] He was the socialist nominee in the 1914 United States Senate election in Oklahoma and the 1918 Oklahoma gubernatorial election.^[3][4] He worked with Oscar Ameringer on Jack Walton's 1922 gubernatorial campaign and later served in Walton's administration until his death on January 12, 1924.^[1]