The calculated distance (air line) between Petrich and Veliko Tŭrnovo is approximately 170 miles respectively 273 kilometers.
By car or train, the actual journey to Veliko Tŭrnovo is certainly longer, as only the direct route (as the crow flies) between Petrich and Veliko Tŭrnovo has been calculated here.
Air line (approximately)
273 kilometers
148 nautical miles