Most obviously, the title North by Northwest names the general direction Thornhill and the other characters are heading: from New York to Chicago by train, then to the Dakotas by plane.

But at another level, the title provides a clue to the role that place and, even more importantly, movement play in the film. Notice that the title doesn't refer to a single place or single, precise set of coordinates on a map: it's not "New York City" or "Mount Rushmore." Instead the film's named for a relationship between multiple places, points A B, C, New York, Chicago, South Dakota, etc. It's as if everything about Hitch's film—even its title—were on the move.

Fun Fact: Some people think that the title is a nod to Hamlet, when Hamlet says about his state of mind: "I am but mad north-north-west. When the wind is southerly, I know a hawk from a handsaw." Hamlet seems to be saying that he's not what he seems to be, confused sometimes but not others, and that sure applies to to Roger Thornhill.