| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| O'Neil (historical) | city | Nevada | United States | 41.78 | -115.02 | 5869 | |
| Oak Springs (historical) | city | Nevada | United States | 37.22 | -116.06 | 5029 | |
| Oasis | city | Nevada | United States | 41.03 | -114.49 | 5869 | |
| Ocala | city | Nevada | United States | 39.91 | -118.74 | 4189 | |
| Ola | city | Nevada | United States | 40.72 | -114.15 | 4586 | |
| Old Battle Mountain (historical) | city | Nevada | United States | 40.61 | -117.06 | 5869 | |
| Old Bullion | city | Nevada | United States | 40.53 | -115.98 | 6709 | |
| Old Camp | city | Nevada | United States | 37.26 | -117.32 | 7598 | |
| Old Overton (historical) | city | Nevada | United States | 36.56 | -114.44 | 1669 | |
| Old Reveille (historical) | city | Nevada | United States | 38.03 | -116.18 | 7125 | |
| Old Tuscarora (historical) | city | Nevada | United States | 41.29 | -116.25 | 5984 | |
| Olinghouse | city | Nevada | United States | 39.66 | -119.43 | 5869 | |
| Omco | city | Nevada | United States | 38.61 | -117.89 | 6171 | |
| Oneota (historical) | city | Nevada | United States | 38.02 | -115.34 | 5029 | |
| Oneota (historical) | city | Nevada | United States | 37.94 | -118.29 | 7650 | |
| Ophir (historical) | city | Nevada | United States | 38.95 | -117.27 | 7811 | |
| Ophir City (historical) | city | Nevada | United States | 39.29 | -119.83 | 5085 | |
| Oreana | city | Nevada | United States | 40.33 | -118.32 | 4189 | |
| Oreana (historical) | city | Nevada | United States | 40.31 | -118.37 | 4189 | |
| Original (historical) | city | Nevada | United States | 36.90 | -116.88 | 4189 | |
| Orizaba (historical) | city | Nevada | United States | 38.51 | -117.62 | 5869 | |
| Orovada | city | Nevada | United States | 41.57 | -117.79 | 4379 | |
| Osceola | city | Nevada | United States | 39.09 | -114.39 | 7565 | |
| Osino | city | Nevada | United States | 40.93 | -115.66 | 5186 | |
| Overton | city | Nevada | United States | 36.54 | -114.45 | 1669 | |
| Overton (historical) | city | Nevada | United States | 41.95 | -118.69 | 4278 | |
| Owyhee | city | Nevada | United States | 41.95 | -116.10 | 5869 |