| Diamond Bar to Orangevale (California) | 375.24 mi (603.89 km) |
| Diamond Bar to Orchards (Washington) | 845.12 mi (1,360.08 km) |
| Diamond Bar to Orcutt (California) | 160.21 mi (257.83 km) |
| Diamond Bar to Oregon (Ohio) | 1,935.39 mi (3,114.70 km) |
| Diamond Bar to Oregon (Wisconsin) | 1,647.04 mi (2,650.65 km) |
| Diamond Bar to Oregon City (Oregon) | 823.43 mi (1,325.19 km) |
| Diamond Bar to Orem (Utah) | 550.03 mi (885.19 km) |
| Diamond Bar to Orinda (California) | 362.53 mi (583.43 km) |
| Diamond Bar to Orland Park (Illinois) | 1,707.68 mi (2,748.24 km) |
| Diamond Bar to Orlando (Florida) | 2,176.89 mi (3,503.36 km) |
| Diamond Bar to Ormond Beach (Florida) | 2,172.12 mi (3,495.68 km) |
| Diamond Bar to Oro Valley (Arizona) | 410.04 mi (659.90 km) |
| Diamond Bar to Oroville (California) | 432.89 mi (696.66 km) |
| Diamond Bar to Oshkosh (Wisconsin) | 1,704.74 mi (2,743.51 km) |
| Diamond Bar to Oskaloosa (Iowa) | 1,460.23 mi (2,350.01 km) |
