I got a Costco question this morning, so I figured it might be time to check and see if there has been any action. In 2012 I discovered a site www.addictedtocostco.com (this isn't a local phenomenon, you see) that features frequent updates on where the chain is building and planning new stores.
Judging by the link, which you can find by clicking here, you fans are going to have to continue driving to Pocatello for a while. The list of stores opening imminently is as follows:
Culiacan, Sinaloa, Mexico -- April 30, 2015
Wichita, Kan. -- June 3, 2015
Mobile, Ala. -- June 4, 2015
Rochester, N.Y. -- June 5, 2015
Perrysburg, Ohio -- June 18, 2015
Pleasant Prairie, Wis. -- June 19, 2015
Saltillo, Coahuila, Mexico -- June 2015
Beyond that, there are stores opening in Japan, Taiwan, Spain, Korea and Canada. Indeed, the world may be Costco's oyster, but poor little Idaho Falls is chopped liver. Sorry.