Nelson Clement Trowbridge, usually doing business as N. C. Trowbridge, was an American businessman who worked as both a merchant and farmer in Poughkeepsie, New York, and a slave trader in the Deep South for approximately 25 years prior to the American Civil War. Trowbridge trafficked in slaves in Virginia, the Carolinas, Georgia, and Louisiana. He also became a plantation owner in Mississippi. He was party to the illegal importation of slaves from Africa on the Wanderer in 1857. Many of the letters written by C. A. L. Lamar about his illegal transatlantic slave trade enterprise of the late 1850s were addressed to Trowbridge ("Trow") in New Orleans. Lamar and Trowbridge, who had had several businesses together, from breeding racehorses to mining for gold, were responsible for at least one blockade-runner, the Ceres, during the American Civil War. Trowbridge was arrested on treason charges twice during the war, and convicted in 1864 of treason and blockade running. The New York Herald and other newspapers deemed him a New York-based Confederate spy and business agent. He seems to have lived in New York City and Mississippi after the war. He died in Mississippi in 1879 and is buried in Augusta, Georgia.