According to Jennifer Lee of the Post, "Washington Post's Tom Toles is this year's winner of the Herblock Prize & Lecture for excellence in editorial cartooning: http://www.herbblockfoundation.org/herblock-prize-winner/737 "
Congratulations to Tom, and that's two Washington winners in a row, as Matt Wuerker took it last year.
Comic Riffs has additional details including noting that Ann Telnaes was a runner-up.