The calculated distance (air line) between Solec Kujawski and Częstochowa is approximately 163 miles respectively 262 kilometers.
By car or train, the actual journey to Częstochowa is certainly longer, as only the direct route (as the crow flies) between Solec Kujawski and Częstochowa has been calculated here.
Air line (approximately)
262 kilometers
141 nautical miles