Well, unknown to me anyway, and it wasn't on shortfield.com either.

Coordinates are: 42.176, -116.854

The guy that told me about it couldn't remember the name of it, and he hadn't landed there in years, so I don't know if it's still open. It looks like there's a plane parked there on the google earth imagery, though. Also, I can see another strip one mile due west of there right beside the river. Does anyone have any information to share?

It's the old 45 Ranch strip, owned by the BLM. It's now listed on the IAA website.

http://idahoaviation.com/idahoAirstripDetail.php?id=46

I updated the shortfield.com database...its in there now. If anyone has photos, videos, PIREPs, or any other additional information, please login and update the airstrip information.
45 Ranch, Idaho
Also, whenever anyone finds strips like this, let me know and I'll add to shortfield so that others (you) can contribute more information you might have.

Thanks for the info Kevbert!