James C. Mahan (born 1943) is a United States federal judge.

Mahan was born in El Paso, Texas. He received a B.A. from University of Charleston in 1965. He received a J.D. from Vanderbilt University Law School in 1973. He was a United States Navy from 1966 to 1969. He was a United States Navy Reserve from 1970 to 1972. He was in private practice of law in Nevada from 1973 to 1999. He was a District Judge, Eight Judicial District Court, State of Nevada from 1999 to 2002.

Mahan was a federal judge to the United States District Court for the District of Nevada. Mahan was nominated by President George W. Bush on September 10, 2001, to a new seat created by 114 Stat. 2762; He was confirmed by the United States Senate on January 25, 2002, and received his commission on January 30, 2002.