The calculated distance (air line) between Balaruc-les-Bains and Marseillan is approximately 10 miles respectively 15 kilometers.
By car or train, the actual journey to Marseillan is certainly longer, as only the direct route (as the crow flies) between Balaruc-les-Bains and Marseillan has been calculated here.
Air line (approximately)
15 kilometers
8 nautical miles