Description
The Monocacy Aqueduct — or C&O Canal Aqueduct No. 2 — is the largest aqueduct on the Chesapeake and Ohio Canal, crossing the Monocacy River just before it empties into the Potomac River in Frederick County, Maryland, USA. The 438 foot (133.5 m) aqueduct was built by three separate contractors between 1829 and 1833 at the cost of US$127,900. The aqueduct is a stone masonry structure with a waterway of 19 feet at the bottom and 20 feet at the top. The towpath parapet wall is 8 feet wide and the upstream wall is 6 feet wide. Benjamin Wright, the project's chief engineer, drew the plans with 6 piers, 2 abutments and 7 arches, each with a span of 54 feet. The piers are 10 feet thick with pilaster at each end. The aqueduct is 438 feet in length. Much of the building material was large quartzite stone blocks quarried at the base of nearby Sugarloaf Mountain.