The speaker is crossing the Willamette River on a rail bridge, leaving Portland, and only in that moment of departure does a feeling arrive: they have fallen in love with the city. It catches them off guard. They once swore they would never love a city, and the poem admits the broken promise with a small, wry "But here I / Am."
The short lines and the line breaks mimic the movement of the trip. The sentence stretches across the bridge, pausing in odd places, and the realization seems to land mid-step, as if the speaker is discovering it while writing. The break before "Am" works like a stumble, a moment of being caught in their own contradiction.
The mood is tender and a little rueful. There's surprise, a touch of humor at having changed their mind, and then plain sadness in "tears of parting." The poem ends on the city's name, as though the speaker can't say more than that. Love, here, shows up only once it's about to be lost.