The calculated distance (air line) between Silistra and Veliko Tŭrnovo is approximately 109 miles respectively 175 kilometers.
By car or train, the actual journey to Veliko Tŭrnovo is certainly longer, as only the direct route (as the crow flies) between Silistra and Veliko Tŭrnovo has been calculated here.
Air line (approximately)
175 kilometers
94 nautical miles