The calculated distance (air line) between Gasa and Samdrup Jongkhar is approximately 133 miles respectively 214 kilometers.
By car or train, the actual journey to Samdrup Jongkhar is certainly longer, as only the direct route (as the crow flies) between Gasa and Samdrup Jongkhar has been calculated here.
Air line (approximately)
214 kilometers
116 nautical miles