Fersah

Fersah was an Ottoman unit of distance.

It was based on the distance covered by a horse in normal gait per hour. Its modern definition (parasang) is 5.685 km (3.532 mi). There were other definitions. According to Islam Encyclopaedia, ıt was sometimes 6.985 km (4.340 mi) or 6.230 km (3.871 mi).