| Castaic to Popovo | 6,621.17 mi (10,655.75 km) |
| Castaic to Provadia | 6,659.71 mi (10,717.77 km) |
| Castaic to Radnevo | 6,677.57 mi (10,746.52 km) |
| Castaic to Radomir | 6,586.84 mi (10,600.49 km) |
| Castaic to Rakitovo | 6,650.01 mi (10,702.16 km) |
| Castaic to Rakovski | 6,654.20 mi (10,708.90 km) |
| Castaic to Razgrad | 6,616.78 mi (10,648.69 km) |
| Castaic to Razlog | 6,639.94 mi (10,685.96 km) |
| Castaic to Ruse | 6,585.78 mi (10,598.79 km) |
| Castaic to Samokov | 6,615.26 mi (10,646.23 km) |
| Castaic to Sandanski | 6,653.82 mi (10,708.29 km) |
| Castaic to Sevlievo | 6,613.52 mi (10,643.43 km) |
| Castaic to Shumen | 6,641.87 mi (10,689.06 km) |
| Castaic to Silistra | 6,598.54 mi (10,619.32 km) |
| Castaic to Sliven | 6,664.08 mi (10,724.80 km) |
