Entrance to Craig Cave in Lava Beds National Monument near Tulelake, California.  The cave is off the beaten path from many of the other caves in the park & has been closed to the public due to white nose syndrome, the closure happening around 2011.  Most of the visitors to this cave for now are scientists & biologists studying animal life underground.  From old map publications, this extends about 1,800 feet while a cave known as Craig Temple goes in from the other end of the collapse sink about 300 feet.