The U.S. Custom House, also known as the Old Post Office and Custom House, is a historic government building at 423 Canal Street in New Orleans, Louisiana. It was designated a National Historic Landmark, receiving this designation in 1974 and noted for its Egyptian Revival columns. Construction on the building, designed to house multiple federal offices and store goods, began in 1848 and didn't finish until 1881 due to redesigns and the American Civil War. The U.S. Customs offices have been located there since the late 19th century.