Cache is located at Stagecoach reservoir. This lake is closed to vehicle traffic (walk-in) only until May 1. If you look during the off season then you will have to walk in from the main road to the south. Small items for trade are encouraged.
The nearby "marker" you see painted white is one of many markers placed by the US Army corps of Engineers as a reference point used to define the endpoints of a cross section that bisects the reservoir or inflowing tributaries. These cross sections are surveyed periodically to determine the amount of erosion and/or deposition that has occurred in the lake since the last survey. This data is then used to determine (among other things) the area and capacity of the reservoir at various pool elevations.