Peter Stenger Grosscup (February 15, 1852 – October 1, 1921) was a United States circuit judge of the United States Court of Appeals for the Seventh Circuit and the United States Circuit Courts for the Seventh Circuit and previously was a United States district judge of the United States District Court for the Northern District of Illinois. Grosscup is best remembered for having made use of the judicial injunction against strikers in labor disputes, including most notably the leadership of the American Railway Union in the 1894 Pullman Strike.

Born on February 15, 1852, in Ashland, Ohio, Grosscup received an Artium Baccalaureus degree in 1872 from Wittenberg College and received a Bachelor of Laws in 1873 from Boston University School of Law. He entered private practice in Ashland from 1873 to 1875. He was city solicitor for Ashland from 1875 to 1881. He resumed private practice in Ashland from 1881 to 1883. He continued private practice in Chicago, Illinois, from 1883 to 1892.^[1]

Grosscup was nominated by President Benjamin Harrison on December 12, 1892, to a seat on the United States District Court for the Northern District of Illinois vacated by Judge Henry Williams Blodgett. He was confirmed by the United States Senate on December 20, 1892, and received his commission the same day. His service terminated on February 1, 1899, due to his elevation to the Seventh Circuit.^[1]

Grosscup was nominated by President William McKinley on January 18, 1899, to a joint seat on the United States Court of Appeals for the Seventh Circuit and the United States Circuit Courts for the Seventh Circuit vacated by Judge John William Showalter. He was confirmed by the Senate on January 23, 1899, and received his commission the same day. His service terminated on October 23, 1911, due to his resignation.^[1]

Grosscup died on October 1, 1921, on board a ship bound for Southampton, England.^[1]