| Forest to Olympia Heights (Florida) | 4,635.15 mi (7,459.56 km) |
| Forest to Omaha (Nebraska) | 4,477.92 mi (7,206.52 km) |
| Forest to On Top of the World Designated Place (Florida) | 4,547.51 mi (7,318.51 km) |
| Forest to Onalaska (Wisconsin) | 4,175.55 mi (6,719.89 km) |
| Forest to Oneida (New York) | 3,623.13 mi (5,830.86 km) |
| Forest to Oneonta (New York) | 3,626.11 mi (5,835.66 km) |
| Forest to Ontario (California) | 5,594.53 mi (9,003.53 km) |
| Forest to Ontario (Oregon) | 5,001.22 mi (8,048.69 km) |
| Forest to Opa-locka (Florida) | 4,622.73 mi (7,439.57 km) |
| Forest to Opelika (Alabama) | 4,497.86 mi (7,238.60 km) |
| Forest to Opelousas (Louisiana) | 4,874.67 mi (7,845.02 km) |
| Forest to Orange (California) | 5,614.90 mi (9,036.30 km) |
| Forest to Orange (Texas) | 4,961.83 mi (7,985.29 km) |
| Forest to Orange City (Florida) | 4,514.26 mi (7,265.01 km) |
| Forest to Orangeburg (South Carolina) | 4,272.95 mi (6,876.64 km) |
