 Thereafter, the Mechanics Bank of Baltimore, where George Brown and Philip E. Thomas were officers, had a leading role in the financing and sale of B&O stock for construction of the first railroad in the U.S. Brown was subsequently elected as the B&O's first treasurer.On December 17, 1818, Brown was married to Isabella McLanahan (1798–1885) in Greencastle, Pennsylvania.Isabella was the daughter of John McLanahan and Elizabeth (née Johnston) McLanahan.