| Prospect Heights to Oak Grove (South Carolina) | 671.29 mi (1,080.33 km) |
| Prospect Heights to Oak Harbor (Washington) | 1,726.98 mi (2,779.31 km) |
| Prospect Heights to Oak Hills (Oregon) | 1,742.63 mi (2,804.50 km) |
| Prospect Heights to Oak Lawn (Illinois) | 28.39 mi (45.69 km) |
| Prospect Heights to Oak Park (California) | 1,751.78 mi (2,819.22 km) |
| Prospect Heights to Oak Park (Illinois) | 16.54 mi (26.62 km) |
| Prospect Heights to Oak Park (Michigan) | 243.76 mi (392.29 km) |
| Prospect Heights to Oak Ridge (Florida) | 1,010.04 mi (1,625.50 km) |
| Prospect Heights to Oak Ridge (New Jersey) | 697.43 mi (1,122.40 km) |
| Prospect Heights to Oak Ridge (Tennessee) | 466.77 mi (751.20 km) |
| Prospect Heights to Oakdale (California) | 1,758.54 mi (2,830.10 km) |
| Prospect Heights to Oakdale (Minnesota) | 321.36 mi (517.18 km) |
| Prospect Heights to Oakland (California) | 1,828.04 mi (2,941.95 km) |
| Prospect Heights to Oakland (New Jersey) | 710.57 mi (1,143.56 km) |
| Prospect Heights to Oakland Park (Florida) | 1,185.46 mi (1,907.81 km) |
