Commonwealth was a large sidewheel steamboat built in 1854–55 for passenger service on Long Island Sound. The most celebrated Sound steamer of her day, Commonwealth was especially noted for the elegance and comfort of her passenger accommodations, which included gas lighting, steam heating, and an "enchantingly beautiful" domed roof in her upper saloon. Her stability of motion led her captain to describe Commonwealth as the finest rough weather steamboat ever built in the United States.