Financier and industrialist Isaac Thomas Mann (July 23, 1863 - May 18, 1932) was born in Greenbrier County. After an apprenticeship at his father's Greenbrier Valley Bank in 1889, Mann helped organize the Bank of Bramwell, which became a financial pillar of the southern coalfields.

Mann visited financier J. P. Morgan in New York in 1901 and in a famous seven-minute interview received backing for an ambitious scheme to acquire coal bearing lands in McDowell County from the Philadelphia-based Flat Top Land Association, a Norfolk & Western Railway affiliate. Mann became suddenly wealthy, powerful, and prominent.

As president of the Bank of Bramwell and president of the Pocahontas Fuel Company for three decades, "Ike" Mann held vast holdings in coal, timber, and especially financial institutions, with investments scattered from Chicago to Mexico City. Mann served as a delegate to the 1908 Republican national convention, and was a serious candidate for the U.S. Senate in 1912. His main residence was a magnificent mansion in Bramwell, where he also built a stone Presbyterian church, but he spent much of his later years at his home in Washington. He also maintained vacation homes in Maine and Florida.

Mann's overextended business empire virtually collapsed in 1929 at the onset of the Depression, and he died at the age of 68 in Washington. Aggressive, competitive, and ambitious, I. T. Mann was one of the few native-born West Virginians to make a fortune in the southern West Virginia coalfields. The Wyoming County town of Itmann is named for him.