The calculated distance (air line) between Yŏnmu and Yeonggwang is approximately 67 miles respectively 109 kilometers.
By car or train, the actual journey to Yeonggwang is certainly longer, as only the direct route (as the crow flies) between Yŏnmu and Yeonggwang has been calculated here.
Air line (approximately)
109 kilometers
59 nautical miles