This paper describes the design and construction of the side-wheel steamer Heroine, a representative of the 'western river steamboat' type and the earliest example of its kind to undergo archaeological study. Heroine was built at New Albany, Indiana, in 1832 and sunk on the Red River between Oklahoma and Texas in 1838. The extensive remains of the lower hull show assembly practices in use during the developmental era of Mississippi River steamboats. The wreck also reveals a heretoforeunknown technique for longitudinally strengthening these long, narrow, and very lightly built hulls.