The calculated distance (air line) between Golub-Dobrzyń and Częstochowa is approximately 160 miles respectively 257 kilometers.
By car or train, the actual journey to Częstochowa is certainly longer, as only the direct route (as the crow flies) between Golub-Dobrzyń and Częstochowa has been calculated here.
Air line (approximately)
257 kilometers
139 nautical miles