Alfred, Lord Tennyson’s poem presents a woman who is confined inside by a magically imposed curse. She cannot leave her room and go outside, a situation that increases her fascination with that alien world. The requirement that she watch these goings-on only through the mirror imposes another layer of separation: because she sees the world in reverse, her vision is distorted by “shadows.” Her mission is to weave, but the subject matter she chooses is “the mirror's magic sights.”
The impossibility of clear vision further isolates her from normal reality. In particular, the Lady of Shalott watches the reflection of the traffic to and from Camelot, King Arthur’s court, as the road which passes beneath her window. The impressive figure of the great Sir Lancelot captures her fancy. It seems that all her pent-up frustrations are condensed in her obsession with him, as she thinks of herself as incomplete without a partner. The poet reveals that the Lady retains a measure of free will, as she is able to defy the terms of her confinement. The price for seeking a partner, however, is death.
As he elaborates on an Arthurian legend, retaining the ancient setting and characters, Tennyson can be understood as relating the theme to the late nineteenth century. The Lady is not simply isolated, but is a social outcast. In the end, the Lady cannot abide by the terms of her confinement, which include the highly gendered task of weaving. The temptation that the noble knight presents is too great to resist. On a metaphorical level, the poet’s Victorian-era readers could understand the association of resistance to conformity as representing a sexual or romantic association outside of the conventionally gendered respectability of marriage.
In addition to the physical and social isolation that the Lady of Shalott must endure within her tower, set apart from all the rest of the world as people come and go beneath her window, she is completely isolated in terms of her punishment as well. "A curse is on her" so that if she stops weaving, she knows that something awful will happen; however, "she knows not what the curse may be." Thus, it seems as though she not only does not know what terrible thing will result if she draws down the curse upon her, but she also does not even know who is responsible for the curse or what caused it.
It is as though the Lady of Shalott is isolated in every conceivable way for no conceivable reason; if this is not utterly and horrifyingly isolating, then I don't know what is. She is punished for she knows not what with a threat of something she cannot know from whence she knows not. It is not clear that she has ever known anyone, as we never hear about her life before the tower or anyone she might have known then. In the end, the most she can hope is that someone will find her body after she has perished, that she will be valued and cared for by someone, somehow, once she is dead.
Much of the poem's poignancy lies in the physical and emotional isolation the Lady of Shalott experiences. In the first three parts, Tennyson builds her isolation until it reaches a crescendo. First, the lady lives on "the silent isle" of Shalott, a piece of ground that stands isolated from the main road that leads to Camelot. Because she never so much as comes to her window, she is not "known in all the land," but the reapers hear her vocal solo. She sees in her mirror many groups of people: "village churls," "market girls," and "a troop of damsels glad." Sometimes she sees individuals traveling past as well, but the knights, interestingly, come by "two and two," and the poet points out that "she hath no loyal knight and true." Seeing the "two young lovers lately wed" is the event that prompts the lady to realize that she is "half sick of shadows," meaning that she is beginning to feel the emotional pain of her isolation. The pairs she sees, the lovers and the pairs of knights, seem to make the isolation even more distressing. When Lancelot appears, he is by himself, but "a red-cross knight forever kneeled to a lady in his shield," pointing out that he, like the lady, was made to be in a man-woman relationship. This sight causes the lady to risk the curse and leave her weaving. When she goes down to the river, no other people seem to be present. She rides alone in the boat toward Camelot. In fact, she dies before she reaches the presence of any people, "ere she reached upon the tide the first house by the waterside." So she dies alone. The people who come to see her are listed in pairs: "knight and burger, lord and dame." Lancelot separates himself from the crowd, however, and speaks a blessing over the lady's dead body. Although it has come too late, she is paired, if only briefly, with Lancelot at the end; that is the first time she has been with another person during the entire poem.
The poem has been interpreted by some as a reflection on the isolation of the artist and by others of the isolation and captivity of the Victorian woman. Either way, the poem poignantly pictures a person who has suffered from physical and emotional isolation in life and in death.