| Grass Valley to Orangevale (California) | 38.11 mi (61.33 km) |
| Grass Valley to Orchards (Washington) | 452.99 mi (729.02 km) |
| Grass Valley to Orcutt (California) | 302.88 mi (487.43 km) |
| Grass Valley to Oregon (Ohio) | 1,969.73 mi (3,169.98 km) |
| Grass Valley to Oregon (Wisconsin) | 1,658.89 mi (2,669.73 km) |
| Grass Valley to Oregon City (Oregon) | 429.96 mi (691.95 km) |
| Grass Valley to Orem (Utah) | 502.03 mi (807.94 km) |
| Grass Valley to Orinda (California) | 110.98 mi (178.61 km) |
| Grass Valley to Orland Park (Illinois) | 1,742.93 mi (2,804.97 km) |
| Grass Valley to Orlando (Florida) | 2,375.37 mi (3,822.79 km) |
| Grass Valley to Ormond Beach (Florida) | 2,361.10 mi (3,799.82 km) |
| Grass Valley to Oro Valley (Arizona) | 733.70 mi (1,180.78 km) |
| Grass Valley to Oroville (California) | 33.31 mi (53.61 km) |
| Grass Valley to Oshkosh (Wisconsin) | 1,699.02 mi (2,734.31 km) |
| Grass Valley to Oskaloosa (Iowa) | 1,498.18 mi (2,411.08 km) |
