North Fork Creek  North Fork Creek is a tributary of Redbank Creek in northwest Pennsylvania in the United States. It is formed by the confluence of Muddy Run and Williams Run in Polk Township, Jefferson County. North Fork Creek and Sandy Lick Creek join to form Redbank Creek in the borough of Brookville, Jefferson County. The political subdivisions North Fork Creek traverses, given in the order they are encountered traveling downstream, are as follows:  The named tributaries of North Fork Creek, given in the order they are encountered traveling downstream, are as follows: