The calculated distance (air line) between Giv'at Shmuel and Ashkelon is approximately 33 miles respectively 52 kilometers.
By car or train, the actual journey to Ashkelon is certainly longer, as only the direct route (as the crow flies) between Giv'at Shmuel and Ashkelon has been calculated here.
Air line (approximately)
52 kilometers
28 nautical miles