The calculated distance (air line) between Halle (Saale) and Roßlau is approximately 30 miles respectively 49 kilometers.
By car or train, the actual journey to Roßlau is certainly longer, as only the direct route (as the crow flies) between Halle (Saale) and Roßlau has been calculated here.
Air line (approximately)
49 kilometers
26 nautical miles