A decent hike up Crown Mound southeast of Hydro. Crown Mound is one of the "Caddo Mounds" that rise up out of the farm lands about 60 miles west of Oklahoma City. The mounds were used as waypoints by wagon trains crossing the territory in the 1800's.
Approach from the north east by exiting Interstate 40 at the Bethel Road exit (Mile 95). The mounds are several hundred feet high and should be the most obvious feature to the southwest. Go south 2.5 miles and turn west. After leaving Bethel Road, you will be on sandy dirt roads, so drive slowly and carefully. The road will turn to the south after 2 miles and it's about .75 miles to the mound. There is an area on the south side of the mound along an oil-field road where you can park.
Keep in mind that this is private property. The Thiessen family allows people to visit the property so long as it isn't abused. If the property has a single wire fence around it, the wire is electrified. The electric wire is to keep cattle on the property, so please don't disconnect it.
At the base of the mound on the north side is a cave. There is also another small cave about 3/4 up on the east side. Check them out!
One final note: Do not take small children to find this cache. The approach to the cache is difficult enough for a healthy adult.