Head out to the Aleutians, they get pretty tiny :-) False Pass, King Cove, Atka, and Nikolksi are pretty small. But I think they're legit for this thread, as they are serviced at least twice a week by a commercial carrier (PenAir, associated with Alaska Airlines).

CDB is nearby, but it used to be an AirForce base and has a 10,000' runway! The locals say it's an alternate landing site for the Space Shuttle, and business jets land all the time to refuel on their way to Asia. It's an interesting sight to see. Back in 2004 a B777 landed there due to engine problems.

Looks like False Pass is the "smallest" with a 2100ft x 75ft runway.