| Castro Valley to Karlovo | 6,507.57 mi (10,472.93 km) |
| Castro Valley to Karnobat | 6,554.79 mi (10,548.91 km) |
| Castro Valley to Kavarna | 6,531.42 mi (10,511.31 km) |
| Castro Valley to Kazanlak | 6,522.21 mi (10,496.49 km) |
| Castro Valley to Knezha | 6,438.38 mi (10,361.57 km) |
| Castro Valley to Kostinbrod | 6,461.13 mi (10,398.18 km) |
| Castro Valley to Kozloduy | 6,413.08 mi (10,320.85 km) |
| Castro Valley to Kyustendil | 6,481.61 mi (10,431.15 km) |
| Castro Valley to Levski | 6,469.61 mi (10,411.83 km) |
| Castro Valley to Lom | 6,399.39 mi (10,298.82 km) |
| Castro Valley to Lovech | 6,475.03 mi (10,420.55 km) |
| Castro Valley to Lukovit | 6,458.83 mi (10,394.49 km) |
| Castro Valley to Lyaskovets | 6,498.80 mi (10,458.80 km) |
| Castro Valley to Mezdra | 6,451.51 mi (10,382.70 km) |
| Castro Valley to Momchilgrad | 6,590.27 mi (10,606.01 km) |
