Thomas Colville has been a private dealer in both American and European fine 19th century paintings, watercolors, and drawings since 1972, helping to broaden the collections of many international museums, corporations, and individuals. While specializing in the works of such American artists as George Inness, John La Farge, James A. McNeill Whistler, Sanford Gifford, Eastman Johnson, and Emil Carlsen, he also maintains a selection of outstanding works from the mid 19th through the early 20th century, in a broad range of prices. Thomas Colville is one of the world's leading dealers in French Barbizon paintings, with a large inventory of works by Corot, Daubigny, Diaz de la Peña, Jules Dupré, Millet, and Rousseau. His showrooms in Guilford, Connecticut and New York are open at any time by appointment.

The "Collections" listed below represent areas of specialization, with works on paper included within these groupings.