Mt. Adams' "Secret" Highway - Potato Hill Road (NF 5603 / BIA 108)

After driving for miles and miles on gravel and dirt roads, we emerged from the woods to find this well constructed, paved highway in the middle of nowhere.  I am sure there is a story behind this, but I am not sure what it is...

We did cross into the Yakima Nation's closed area, not quite sure if we were allowed to or not, since the signs telling us not to were very small and hard to see from the car.

               

I haven't been able to find any references to this, but I seem to remember something years ago about the Yakima Tribes wanting to build a more direct highway from the reservation to the west side of the mountains, and maybe even building their end of it, but then failing to get the state to build its end.  So, this might be that highway.  It was well engineered and one could easily roll down into the valley at 65 on this bad boy, except for a few rather nasty potholes that have developed since the road was paved last.

But this might just be a figment of my overactive imagination.  Maybe it is just an access road...  If anyone knows anything, let me know!

Yakama Nation Mt. Adams Recreation Area (Tract D):
http://www.ynwildlife.org/Recreation.php

Mount Adams Recreation Area Overview:
http://www.ynwildlife.org/pdf/Brochure2011p2%20Final%20(2).pdf

YAKAMA NATION - Mt. Adams Recreation Area - Snowmobiling & Winter Public Use Prohibited:
http://mtadamsfriends.org/wordpress/wp-content/uploads/2011/04/Mt.-Adams-brochure-10-23-10.pdf