The calculated distance (air line) between Crépy-en-Valois and Saint-Quentin-en-Yvelines is approximately 51 miles respectively 82 kilometers.
By car or train, the actual journey to Saint-Quentin-en-Yvelines is certainly longer, as only the direct route (as the crow flies) between Crépy-en-Valois and Saint-Quentin-en-Yvelines has been calculated here.
Air line (approximately)
82 kilometers
44 nautical miles