William Forgy McNagny (April 19, 1850 – August 24, 1923) was a U.S. Representative from Indiana. Born in Tallmadge, Ohio, McNagny moved in early life to Whitley County, Indiana. He attended the public schools and Springfield Academy in South Whitley, Indiana. He then taught school while working on his father's farm for six years. From 1868 to 1875, he served as the Larwill, Indiana station agent for the Pennsylvania Railroad. After leaving Congress, McNagny resumed the practice of law in Columbia City. He died in Columbia City on August 24, 1923 and was interred in the city's Masonic Cemetery.