The calculated distance (air line) between Chiang Khong and Chiang Rai is approximately 44 miles respectively 71 kilometers.
By car or train, the actual journey to Chiang Rai is certainly longer, as only the direct route (as the crow flies) between Chiang Khong and Chiang Rai has been calculated here.
Air line (approximately)
71 kilometers
39 nautical miles