Dear Jonathan Rosenbaum:
Richard Linklater and the publicity staff of Waking Life may insist that their film contains "no geographical references," but aside from the "incidental," allusive representation of Austin that you noticed (via a shot of the state capitol building), another concrete, unequivocal example exists in the film.
The bridge that Speed Levitch and Wiley Wiggins walk on is, for two explicit reasons, the Brooklyn Bridge. No other bridge in New York (or anywhere) swoops with such astounding crossbracing; its architecture was rendered, despite the film's otherwise displacing cinematography, unmistakably.
In the scene, Levitch quotes a poem by Lorca without naming it, but tells Wiggins it's about the bridge that they're on. Lorca's poem, "Nocturno del Brooklyn Bridge (Brooklyn Bridge Nocturne)," was published in 1940 in Poet in New York. Levitch and Wiggins appear to be walking out of lower Manhattan, into Brooklyn, but the skyline behind them betrays a conspicuous, dreamlike absence: the Twin Towers.