The calculated distance (air line) between Nahiyat Ghammas and As Samawah is approximately 49 miles respectively 79 kilometers.
By car or train, the actual journey to As Samawah is certainly longer, as only the direct route (as the crow flies) between Nahiyat Ghammas and As Samawah has been calculated here.
Air line (approximately)
79 kilometers
42 nautical miles