The calculated distance (air line) between Praga Południe and Ostrołęka is approximately 62 miles respectively 99 kilometers.
By car or train, the actual journey to Ostrołęka is certainly longer, as only the direct route (as the crow flies) between Praga Południe and Ostrołęka has been calculated here.
Air line (approximately)
99 kilometers
54 nautical miles