Where sea beats where waves break here is an end to land
Here gulls surge not caustic as the hawk drifting over Wyoming
Here where trails halt wheels must cease continual turning
Here at last the West and plows must feed man must breed
Oregon, in these lines, is the place where westward movement finally stops. The speaker stands at the coast, where the sea beats against the shore and there is "an end to land." Everything that follows grows out of that sense of arrival. The gulls here seem gentler than the "caustic" hawk the speaker remembers over Wyoming, so the ocean feels like a softer country than the dry interior behind it. Then the poem turns to travel itself: trails halt, and wheels must stop their "continual turning."
The last stanza is the most interesting. With no more frontier to push toward, the poem suggests, people have to settle: plows must feed, and "man must breed." The tone is a mix of relief and finality. There is quiet satisfaction in reaching the edge, but also a note of necessity, as if staying put means putting down roots and getting on with ordinary life. The short lines and plain words give it a stripped, steady feel.