The calculated distance (air line) between Épernon and Paris 18 Buttes-Montmartre is approximately 36 miles respectively 58 kilometers.
By car or train, the actual journey to Paris 18 Buttes-Montmartre is certainly longer, as only the direct route (as the crow flies) between Épernon and Paris 18 Buttes-Montmartre has been calculated here.
Air line (approximately)
58 kilometers
32 nautical miles