A Grotto is an internal organization of the National Speleological Society (NSS).
They generally function as the local NSS chapter/club.
[1] Regions are also an internal organization of the National Speleological Society.
These include:[2] An annual report describing various aspects of the Grotto is submitted to the NSS.
It was chartered in 1941 with Clay Perry as president and Ned Anderson as vice-president.