The calculated distance (air line) between Grand-Couronne and Saint-Quentin-en-Yvelines is approximately 61 miles respectively 98 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 Grand-Couronne and Saint-Quentin-en-Yvelines has been calculated here.
Air line (approximately)
98 kilometers
53 nautical miles