The 27% it missed were mostly cave entrances on bluff faces, cliffsides, or under really dense canopy where ground-return LiDAR is sparse. Some are caves where the recorded coordinates are off. Hard limits of the data, not bugs in the app.

The site has ~5,000 publicly-known US cave locations for reference. Most cave locations are private and should stay that way. CaveFinder.app finds caves from public LiDAR data.