The 1859 Jail, Marshal's Home and Museum is one of Independence's grittier historic sites. The old county jail held thousands of prisoners through the Civil War era, including Frank James after the James gang years had made the family name infamous.
The cells are stark, cramped, and useful for understanding a harsher side of western Missouri history than the wagon-trail stories nearby. Pair it with the National Frontier Trails Museum or the Truman sites if you are making a half-day trip from Kansas City to Independence.