This is an elegant poem. It is by no means the most psychologically rich poem Frost ever wrote, yet in its starkness and clarity we as readers only benefit. Perhaps the first thing we notice is that the poem is an interior monologue. The first line establishes the tone of a person musing quietly to himself on the situation before him: "Whose woods these are I think I know." He pauses here on "the darkest evening of the year," the point in time poised between the day and the night, between consciousness and unconsciousness, between waking and sleeping, between life and oblivion. There is a slight lack of surety in the speaker saying to himself, "I think I know," thus again signifying the meeting ground between what he knows and what he does not. These antimonies, his lack of certainty, and the muted sense of passion provide the tension by which the poem operates.
The reader will notice along with this that the first line consists entirely of monosyllables. Typically, monosyllabic lines are difficult to scan, yet Frost, having written the poem almost entirely in monosyllables demonstrates by this his technical prowess, as the poem scans in perfect iambic tetrameter. And so, any lack of certainty we might first suspect is smoothed over by this regular rhythm. Frost, likewise, stabilizes the poem by the rhyme scheme of aaba/ bbcb/ ccdc/ dddd, without a single forced rhyme. This combination of regular rhythms and rhymes produces a pleasant hypnotic effect, which only increases as the poem progresses. Richard Gray has marked this in explaining how the poem moves from a more conversational tone to the charming effect that characterizes the ending. The language does indeed demonstrate this change: we move from the colloquial "His house is in the village though" to the poetic "Of easy wind and downy flake// The woods are lovely, dark and deep."
If there is any generalization that is apt to describe Frost’s poetics, it is that his characters are almost always of two minds. John Ogilvie has noted the slight contrast between the speaker’s public obligations and his private will. The speaker, we may assume, is "half in love with easeful death." Yet, though the poem is an interior monologue, the speaker does not look inward; rather, he focuses on recreating in his imagination the sense of his surroundings. Indeed, he seems much more conscious of his surroundings than he is of the inner-workings of his mind (which, at least for the reader remain nearly as inscrutable as the dark woods). In such a way, the speaker by implication hints that the outer-wilderness corresponds to his inner one. This is of course most evident in the final refrain in which the outward journey becomes a symbol for his inner journey, but it is furthered by the concentration on his perception of his surroundings; in other words, by opening his mind to the surroundings rather than sealing it off in self-referential language, he becomes what he beholds, or, to quote another poem which most certainly was influenced by this one:
On must have a mind of winter
To regard the frost and the boughs
Of the pine-trees crusted with snow
Richard Poirier has marked that "woods" is mentioned four times in the poem. Along with this the reader will note that "I" is mentioned five times. These two realities, the subjective and the objective, are merged over the course of the poem. Such that, while the speaker focuses almost exclusively on the physical fact of his surroundings, he is at the same time articulating his own mental landscape, which seems ever-intent "to fade far away, dissolve, and quite forget." There is in the end the uncertainty in choosing between his death impulse and his desire to continue on the road of life. Which wins in the end, I think I know, but it scarcely matters; the speaker has had his solitary vision; whether he stays or goes, the woods will go with him and the reader, who are now well-acquainted with the coming night.