Survey Index U
| CAVE/COUNTRY | REGION/EXTENSION | REFERENCE |
|---|---|---|
| Uachdar, Uamh nan | 103:33 | |
| area maps | 103:32 | |
| Uamh an Claonaite | 50:30, 126:31, 204:12 | |
| Sumps 4-6 | 113:22 | |
| The Treen Scene | 107:19 | |
| Uamh an Coire Domhain | 109:16 | |
| Uamh an XXXX | 109:17 | |
| Uamh na h-Aiseirgh | Ashery Pot | 272:12, 274:12, 277:10 |
| Uamh na Sgoltaidh Dhuibe | 79:18 | |
| Uamh nan Clachan Dubhan | 266:19 | |
| Uamh nan Claig-Ionn | 37:6 | |
| Uamh nan Naomh Seras | 155:17 | |
| Uamh nan Uachdar | 103:33 | |
| area map | 103:32 | |
| Uamh Sgeinne | 19:16 | |
| Ukraine | Optimisticheskaja | 98:33, 206:21 |
| Ullet Gill Cave | 98:13 | |
| Upper ANUS Cave 4 | 107:18 | |
| Upper Canada Cave | 197:12, 244:11 | |
| with The Paddock extension | 245:7 | |
| with The Log Pile extension | 248:8 | |
| Upper Cradle Hole | 208:11 | |
| Upper Flood Swallet | 193:21, 195:10 | |
| Chuckle’s Joke | 217:17 | |
| East Passage and Rift Series | 205:16 | |
| Golden Chamber extensions | 189:16, 191:18 | |
| Upper Hackergill Cave | 127:9 | |
| Upper Lathkill | caves of | 97:10 |
| UNCABAC | 254:31 | |
| Ural | Kapova Cave | 121:38 |
| Urchin Cave (Green Holes) | 76:13 | |
| USA | Barrack Zourie Cave | 109:18 |
| Black House Mountain System | 136:23 | |
| Blue Spring Cave | 98:17 | |
| Crabby Cave | 106:26 | |
| Green Fork Falls Cave | 34:41 | |
| Hawaii, area map | 42:20 | |
| Hawaii, Kazamura Cave | 118:25 | |
| Jewel Cave | 206:23 | |
| Kathy’s Icebox | 34:41 | |
| Lechuguilla Cave | 79:34-5, 206:22, 269:26-7 | |
| Lechuguilla Cave: Higher Education | 269:27 | |
| Lechuguilla Cave: Neuland | 251:30,31 | |
| Mammoth Cave System | 206:20 | |
| Mammoth/Flint Ridge System | 23:24 | |
| No Business Blowing Cave | 81:34-5 | |
| Three Door Cave | 106:26 | |
| Wakulla Springs | 137:22 | |
| Wind Cave | 259:34 | |
| Zicafoose Blowhole | 183:27 | |
| Uwd Lwyd, Ogof yr | 187:27 | |
| Uzbekistan | Boybuloq | 282:28-9 |
| Visnevsku | 282:28-9 |