Sylvester Marsh (September 30, 1803 – December 30, 1884) was an American merchant and inventor who designed and built the Mount Washington Cog Railway.

Born in September 1803,[1] Marsh grew up on a farm, which he worked on, and he attended the common school in the winter.

He resided a year in Brooklyn, New York, where he was an exporter, sending much of his dried meal product to the West Indies.

[1] While ascending Mount Washington in 1852, Marsh lost his way, and then conceived the idea of building a railroad to its summit, believing that such an enterprise could be made profitable.

[4] Notwithstanding all opposition, Marsh persisted in building the railroad, relying chiefly on his own resources, and received little capital investment until an engine was actually running over part of the route.