The calculated distance (air line) between Middelburg and Graaff-Reinet is approximately 59 miles respectively 96 kilometers.
By car or train, the actual journey to Graaff-Reinet is certainly longer, as only the direct route (as the crow flies) between Middelburg and Graaff-Reinet has been calculated here.
Air line (approximately)
96 kilometers
52 nautical miles