| Ottawa to Odenton (Maryland) | 658.80 mi (1,060.23 km) |
| Ottawa to Odessa (Texas) | 993.14 mi (1,598.30 km) |
| Ottawa to Ogden (Utah) | 1,197.84 mi (1,927.74 km) |
| Ottawa to Oildale (California) | 1,676.90 mi (2,698.72 km) |
| Ottawa to Ojus (Florida) | 1,173.36 mi (1,888.35 km) |
| Ottawa to Okemos (Michigan) | 244.88 mi (394.10 km) |
| Ottawa to Oklahoma City (Oklahoma) | 621.28 mi (999.85 km) |
| Ottawa to Okmulgee (Oklahoma) | 554.79 mi (892.84 km) |
| Ottawa to Olathe (Kansas) | 359.70 mi (578.88 km) |
| Ottawa to Old Jamestown (Missouri) | 190.16 mi (306.04 km) |
| Ottawa to Oldsmar (Florida) | 982.84 mi (1,581.73 km) |
| Ottawa to Olean (New York) | 538.05 mi (865.91 km) |
| Ottawa to Olive Branch (Mississippi) | 445.27 mi (716.60 km) |
| Ottawa to Olivehurst (California) | 1,723.72 mi (2,774.05 km) |
| Ottawa to Olney (Maryland) | 637.82 mi (1,026.47 km) |
