The calculated distance (air line) between Thủ Dầu Một and Củ Chi is approximately 11 miles respectively 17 kilometers.
By car or train, the actual journey to Củ Chi is certainly longer, as only the direct route (as the crow flies) between Thủ Dầu Một and Củ Chi has been calculated here.
Air line (approximately)
17 kilometers
9 nautical miles