The collection consists of letters to Hamilton Smith from Dartmouth College friends and others, 1823-1833; a few letters relating to Smith's law practice; manuscripts of some of Smith's writings and letters relating to them; letters in regard to the American Cannel Coal Company of Cannelton, Indiana, 1849-1860, and coal mining in general; letters on cotton manufacturing, 1848-1860, on the Cannelton Cotton Mill, 1849-1851, and on tariffs on cotton, 1850-1869; and letters on proposed railroads in the Middle West and Far West, 1848-1872. There are letters on emigration from the eastern states to Cannelton and a letter of May 28, 1851, from Joseph Kundek, Catholic priest, to Hamilton Smith offering to serve as an agent to attract German emigrants to Cannelton. A letter of January 7, 1850, from John W. Powell to Hamilton Smith relates to the building of a Methodist Church at Cannelton. There is a folder of photographs and other pictures, including a carte de visite photograph of General Philip Henry Sheridan and an ink sketch of Duff Green.

Bound volumes of Hamilton Smith's in the collection include a diary, September 19, 1827-October 21, 1829; a memorandum book, dated Dartmouth College, May 12, 1837-June 8, 1848; a scrapbook of newspaper and other clippings, 1849- 1873, being in the main articles written by Hamilton Smith; and a scrapbook of clippings, 1848-1871, relating principally to manufactures.

Correspondents represented in the collection include Nathaniel Albertson, James Tyler Ames, Charles I. Battell, William Van Ness Bay, Thomas Bellows, Charles Guilford Burnham, Federal Burt, Charles Butler, John Nicholson Campbell, Henry Charles Carey, Francis Yates Carlile, Salmon Portland Chase, Charles Dexter Cleveland, Walter Coulton, Stephen Colwell, Freeman Converse, John Jordan Crittenden, Charles Backus Dana, James Dunwoody Brownson DeBow, William Henry Duncan, Millard Fillmore, Nathaniel Smith Folsom, James W. Forsyth, William M. Franklin, James Henry Hammond, James Harrison, Thomas Andrews Hendricks, Elisha Mills Huntington, John Ingle, Charles Tillinghast James, Walter Rogers Johnson, Benjamin Labaree, John Law, Henry Richard Linderman, Arthur Livermore, Nathan Lord, Hermann Ernest Ludewig, Hugh McCulloch, John McGill, Frederick Marryat, Humphrey Marshall, Martin Marty, Charles H. Mason, Samuel Merrill, Gouverneur Morris, David Dale Owen, Robert Dale Owen, Leonidas Polk, Henry Varnum Poor, Jacob Hooke Quimby, Henry Jarvis Raymond, Ignatius Aloysius Reynolds, Tobias Gibson Richardson, Henry Darwin Rogers, Chauncey Rose, John Sanders, Benjamin Bosworth Smith, Richard Smith, Martin John Spalding, Mrs. Katherine Jane (Chase) Sprague, Hannibal Stone, Noah Haynes Swayne, Sir Edward Thornton, George Upfold, Daniel Wolsey Voorhees, Edmund Quincy Waldron, Asa Whitney, William B. Whiting, Levi Woodbury, Charles William Woodman, Joseph Albert Wright, and Timothy Roberts Young.