sentences:  Between 1800 and 1860, Floyd County experienced a huge boom in population (doubling many times over).A survey in the 1850s found that over half of Indiana's population that made more than $100,000 per year lived in Floyd County, establishing it as having the richest population in the state.The Duncan Tunnel, the longest tunnel in Indiana, was built in Floyd County in 1881 between New Albany and Edwardsville.