The calculated distance (air line) between Griñón and San Martín de la Vega is approximately 15 miles respectively 24 kilometers.
By car or train, the actual journey to San Martín de la Vega is certainly longer, as only the direct route (as the crow flies) between Griñón and San Martín de la Vega has been calculated here.
Air line (approximately)
24 kilometers
13 nautical miles