The calculated distance (air line) between Saint-Just-en-Chaussée and Saint-Quentin-en-Yvelines is approximately 54 miles respectively 87 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 Saint-Just-en-Chaussée and Saint-Quentin-en-Yvelines has been calculated here.
Air line (approximately)
87 kilometers
47 nautical miles