Actually, 60. He said he'd visited 57, had one more to go, and that he wasn't allowed to visit AK and HI.
Original quote: "It is wonderful to be back in Oregon," Obama said. "Over the last 15 months, we’ve traveled to every corner of the United States. I’ve now been in 57 states? I think one left to go. Alaska and Hawaii, I was not allowed to go to even though I really wanted to visit, but my staff would not justify it."
Cool. More info about our geography-challenged ex-president. Thanks. Sixty states.