The calculated distance (air line) between Sint-Martens-Lennik and La Louvière is approximately 22 miles respectively 36 kilometers.
By car or train, the actual journey to La Louvière is certainly longer, as only the direct route (as the crow flies) between Sint-Martens-Lennik and La Louvière has been calculated here.
Air line (approximately)
36 kilometers
20 nautical miles