When iOS 9 arrives this fall, Apple Maps will display whether a particular location supports Apple Pay. But if you want to see a master list of all the retailers that Apple knows is on board, hit the link in the headline. It’s probably worth bookmarking, too.
Note that a retailer does not have to specifically support Apple Pay or display its icon. If their terminal displays the NFC payments icon below (also sometimes referred to as the “contactless payments” icon), and as long as the retailer was not so shortsighted as to deliberately block Apple Pay, it should work just fine.