 While the 1997 version of the Mindego Hill 7.5 minute quadrangle does not show Middleton Tract Road, it diverges east from Portola Park Road at a location called Crockers Curve (USGS feature ID 221842, NAD27 coordinates) .There are about two dozen mail boxes on the west side of Portola Park Road at this location.The intersection of Slate Creek Road and Portola Park Road is located approximately at latitude and longitude (NAD27).