Overview Tumwater Campground, located at the confluence of Chiwaukum Creek and the Nenatchee River in the Okanogan-Wenatchee National Forest, offers a serene setting for groups and large gatherings.Recreation Tumwater Group Campground offers outdoor enthusiasts the opportunity to hike, fish, ski and enjoy a long list of outdoor recreational activities throughout the year. The confluence of Chiwaukum Creek and the Nenatchee River offers anglers a scenic backdrop as they cast their lines into th