| GILLETTE, CITY OF | 32,222 | 6 | Detected |
| WRIGHT WATER & SEWER DISTRICT | 2,500 | 8 | — |
| SLEEPY HOLLOW SUBDIVISION | 2,400 | 24 | — |
| ANTELOPE VALLEY I&S DISTRICT (AVISD) | 1,280 | 11 | — |
| FOX PARK SUBDIVISION | 843 | 8 | — |
| HERITAGE VILLAGE SUBDIVISION | 750 | 18 | — |
| FOOTHILLS MOBILE HOME PARK | 735 | 1 | — |
| EASTVIEW MANUFACTURED HOME COMMUNITY | 688 | 4 | — |
| BLACK THUNDER COAL MINE | 600 | 1 | Detected |
| NAVAJO TRANS ENRG. CO., LLC (CORDERO) | 550 | 4 | — |
| CRESTVIEW ESTATES SUBDIVISION | 500 | 10 | — |
| WESTVIEW MHC | 416 | 1 | — |
| MEANS IMPROVEMENT & SERVICE DISTRICT | 410 | 13 | — |
| NICKELSON FARMS WATER COMPANY | 400 | 3 | — |
| FREEDOM HILLS SUBDIVISION | 400 | 32 | — |
| COUNTRYSIDE WATER USERS, INC. | 360 | 19 | — |
| ROCHELLE COAL MINE | 306 | 7 | — |
| HIGHVIEW MFG MOBILE HOME COMMUNITY (MHC) | 304 | 46 | — |
| EAGLE SPECIALTY MATERIALS, LLC-BELLE AYR | 300 | 3 | — |
| EAGLE SPECIAL. MATS, LLC-RAWHIDE SCHOOL | 295 | 30 | — |
| COOK ROAD WATER DISTRICT | 291 | 12 | — |
| EAGLE SPEC. MAT., LLC-EAGLE BUTTE MINE | 277 | 25 | — |
| CEDAR HILLS WATER ASSOCIATION | 258 | 29 | — |
| WRANGLER ESTATES | 250 | 273 | — |
| POWDER RIVER COAL-RAWHIDE MINE | 235 | 8 | — |
| AMERICAN ROAD W&S DISTRICT | 220 | 25 | — |
| POWDER RIVER COAL-CABALLO MINE | 200 | 22 | — |
| STONE GATE ESTATES | 198 | 10 | — |
| FORCE ROAD JOINT POWERS BOARD | 195 | 22 | — |
| PEOPLE`S IMPROVEMENT & SERVICE DISTRICT | 176 | 78 | — |
| LEX MOBILE HOME PARK | 172 | 1 | — |
| NORTH ANTELOPE COAL MINE | 170 | 2 | — |
| BLACK HILLS POWER INCORPORATED | 154 | 10 | — |
| SOUTHFORK ESTATES | 144 | 25 | — |
| BENNOR ESTATES & IMPROVEMENT DISTRICT | 144 | 52 | — |
| EAGLE RIDGE MHP, LLC | 140 | 287 | — |
| GREEN VALLEY ESTATES I&S DISTRICT | 140 | 22 | — |
| NORTH GURLEY MOBILE HOME PARK | 128 | 6 | — |
| EIGHT MILE SUBDIVISION | 120 | 6 | — |
| SECTION 4 WATER SYSTEM INCORPORATED | 120 | 15 | — |
| COAL CREEK MINE-THUNDER BASIN COAL CO | 105 | 2 | — |
| HOY MOBILE HOME PARK | 100 | 48 | — |
| PLAY PARK LLC | 96 | 9 | — |
| LOS COMALES LLC | 90 | 17 | — |
| ROZET RANCHETTES I&S DISTRICT | 85 | 12 | — |
| BUCKSKIN MINING COMPANY-KIEWIT CORP | 80 | 8 | — |
| WARD CREEK LANDOWNERS ASSOCIATION | 77 | 219 | — |
| SCHOOL CREEK MINE | 75 | 24 | — |
| PINEVIEW I&S DISTRICT | 75 | 53 | — |
| DRY FORK STATION | 75 | 27 | — |