Flood risk models in karst landscapes often use methods that do not capture the complex linkages between surface water and groundwater flow. Therefore, published maps for access to the National Flood Insurance Program may exclude those who experience regular inundation. Using simple geographic information system–based inundation models, we demonstrated how one town in Indiana, Orleans, in the classic karst landscape of the Lost River watershed, has been systematically excluded from flood insurance risk maps because Federal Emergency Management Agency–produced models do not consider the town to be prone to floods, despite well-documented evidence to the contrary. Our simple models connect missing elements to the National Hydrography Dataset and show that published flood insurance rate maps significantly under-predict the possible scope of floods in this watershed. Recently proposed highway infrastructure included alternatives that would have bisected the Lost River watershed and could have potentially increased flooding concerns. Unless comprehensive studies detail the actual risk of floods as (1) part of the natural landscape response in karst, (2) a natural consequence of more extreme events as climate changes, and (3) a consequence of impaired flow routes possible from road construction, towns such as Orleans may experience amplified economic exclusion.