The calculated distance (air line) between Svay Rieng and Phnom Penh is approximately 68 miles respectively 110 kilometers.
By car or train, the actual journey to Phnom Penh is certainly longer, as only the direct route (as the crow flies) between Svay Rieng and Phnom Penh has been calculated here.
Air line (approximately)
110 kilometers
59 nautical miles