"At Castle Boterel" is one of many elegies Thomas Hardy wrote after the death of his first wife, Emma Gifford. After a long, mostly unhappy marriage, Gifford took ill and died suddenly, leaving Hardy to wrestle with his grief and guilt over how he had treated her. This poem reflects on the couple's tender courtship, which was so unlike the difficult years that followed.
"Castle Boterel" is another name for Boscastle, the English fishing village where Hardy and Gifford met and fell in love. The title thus alludes to their courtship. Yet the poem begins in the present, with Hardy revisiting the place many years later. (In real life, he did, in fact, return to Cornwall after her death to reflect on their relationship.)
The speaker—Hardy himself—is "driv[ing] to the junction of lane and highway." In other words, he's turning onto the highway from a smaller road. A persistent rain soaks his horse-drawn carriage. The image of a gray, "bedrench[ing] drizzle" creates a somber atmosphere, appropriate to a poem of mourning. The harsh, drumming /dr/ consonance in these lines ("drive," "drizzle," "bedrenches") has a similar effect.
As he drives, Hardy "look[s] behind" him "at the fading byway": the little lane disappearing from view. Peering over his shoulder, he can clearly "see" something on the hill's "slope" despite the "glistening" rain. After four end-stopped lines, sudden enjambment propels the reader across the stanza break:
And see on its slope, now glistening wet,
Distinctly yet
Myself [...]
The pause creates a moment of suspense, leaving the reader to wonder, briefly, what the speaker is seeing.
By the end of this first stanza, Hardy has also established the poem's form. "At Castle Boterel" is written in accentual meter (meaning its lines contain a set number of stressed syllables, but those stresses don't follow a consistent pattern). Accentual meter is relatively flexible and tends to create a loose, lilting rhythm. At the same time, it's more orderly than free verse, and this poem's steady ABABB rhyme scheme lends additional structure. These formal features carry across seven tidy quintains (five-line stanzas), so the poem feels very controlled overall.