The Green Bay Tributary of the Fox River is 200+ miles long ENDS in Lake Michigan in the City of Green Bay then flows southwest through Kaukanna WI, Appleton WI, Menasha WI, Neenah WI into Lake Winnegabo (Wisconsin's Largest Inland Lake). Then continues northwest into Lake Butte Des Morts and exits flowing again southwest to Waushara County for only about a 3 to 4 mile stretch going through the City of Berlin. This is where the Fox River get's much smaller still flowing southwest to Princeton WI, then flows into Pukaway Lake then flows northwest to into Buffalo Lake the turns south down to Portage WI. From the Portage area the river turns to the east through Swan Lake and Park Lake where the Fox River Headwaters are found in a swampy area by the Columbia County and Green Lake County Border.
Fox River - https://thelandman.net/fox-river-wisconsin.html