How many kilometers is Ningyuan River?

83.5 kilometers. According to an article published by Netease News, Ningyuan River originates from Hongshuiling in Baoting, flows from northeast to southwest, and enters the sea at Baoping Port in Yazhou District of Sanya, with a total length of 83.5 kilometers. The general flow is 253 cubic meters per second, the average width of riverbed is 70 meters, and the drainage area is about 630 square kilometers.