Thomas Clark Durant, (1820 – 1885) was a financier and railroad promoter. He was vice-president of the Union Pacific Railroad (UP) in 1869 when it met with the Central Pacific railroad. He was successful in building railroads in the Midwest, and, after the UP was organized in 1862 by an act of Congress, John A.Dix was elected president and Durant vice president of the company.

The burden of management and money raising was assumed by Durant, and, with much money at his disposal, he helped to secure in 1864 the passage of a bill that increased the land grants and privileges of the railroad. He organized and at first controlled the Crédit Mobilier of America, but in 1867 he lost control of the company to Oakes Ames and his brother, Oliver Ames,Jr. Durant, however, continued on the directorate of the Union Pacific and furiously pushed construction of the railroad until it met the Central Pacific RR on May10, 1869. The Ames group then procured his discharge.