The Frank Littleton Round Barn, also known as the "Littleton-Pulliam Round Barn", is a round barn near Mount Comfort, Indiana, United States. Built in 1903, it was listed on the National Register of Historic Places in 1993. The barn's design was used as documentation in a U.S. patent application, "Improvements to the Self-Supported Conical Roof", a patent which was granted in 1905 to Littleton, Isaac McNamee and Horace Duncan. A 1991 study indicates that "many farmers began building multi-sided (6, 8, 10, 12, 14 and 16-sided) barns to skirt ... infringement" upon the patent.