| Niagara Falls to Oliveira de Frades | 3,533.60 mi (5,686.78 km) |
| Niagara Falls to Oliveira do Bairro | 3,525.31 mi (5,673.43 km) |
| Niagara Falls to Oliveira do Hospital | 3,560.04 mi (5,729.33 km) |
| Niagara Falls to Ourem | 3,550.28 mi (5,713.63 km) |
| Niagara Falls to Ovar | 3,507.94 mi (5,645.48 km) |
| Niagara Falls to Pacos de Ferreira | 3,506.07 mi (5,642.48 km) |
| Niagara Falls to Palmela | 3,570.41 mi (5,746.03 km) |
| Niagara Falls to Paredes | 3,511.26 mi (5,650.83 km) |
| Niagara Falls to Paredes de Coura | 3,478.40 mi (5,597.94 km) |
| Niagara Falls to Penacova | 3,543.32 mi (5,702.43 km) |
| Niagara Falls to Penafiel | 3,513.35 mi (5,654.19 km) |
| Niagara Falls to Peniche | 3,522.52 mi (5,668.94 km) |
| Niagara Falls to Peso da Regua | 3,538.08 mi (5,693.99 km) |
| Niagara Falls to Pinhal Novo | 3,567.61 mi (5,741.51 km) |
| Niagara Falls to Pinhel | 3,583.14 mi (5,766.50 km) |
