Municipalities lying within the Pathfinder to Guernsey subbasin include Casper, Douglas, Glenrock, and Guernsey. The Pathfinder to Guernsey subbasin lies within a large portion of Natrona and Converse Counties, a small southwestern area of Niobrara County, a large northern portion of Platte County, and small northern areas of Carbon and Albany Counties. Interstate Route I-25 runs through the Pathfinder to Guernsey subbasin connecting the Towns and Cities of Douglas, Glenrock and Casper, Wyoming. U.S. Route 26 connects Guernsey, Wyoming to Interstate Route I-25 and then runs west out of Casper. U.S. Route 18/20 intersects Interstate Route I-25 south of Douglas, Wyoming and runs west out of Casper with U.S. Route 26. Many state highways intersect Interstate Route I-25 within the Pathfinder to Guernsey subbasin.