Antelope Springs Cave

Antelope Springs is the 10th longest cave in Utah at .61 miles. It is gated, and managed by the BLM in Fillmore Utah. From the Timp Grotto site:

Antelope Springs Cave: This Cave is owned and managed by BLM Office in Fillmore, Utah. The cave is closed from April to September to protect a maternity colony of Townsend's big-eared bats. At other times, caving groups meeting certain minimal standards may obtain the key. Some requirements are: a limit of 10 people/trip maximum, 3 people/trip minimum, one group/day, and hardhats required. Arrangements for a key can be made by through the BLM Office in Fillmore, (435) 743-6811. The non-duplicatable key is normally mailed to you.

It has an 'easy' vertical entrance with a short vertical drop, then a sloping drop to the bottom. Many just use a handline to enter, although an ascender makes the top part much easier.