Although the "Lucy poems" share stylistic and thematic similarities, it was not Wordsworth but literary critics who first presented the five poems as a unified set called the "Lucy poems". The grouping was originally suggested by critic Thomas Powell in 1831 and later advocated by Margaret Oliphant in an 1871 essay. The 1861 Golden Treasury, compiled by the English historian Francis Palgrave (1788–1861), groups only four of the verses, omitting "Strange fits". The poems next appeared as a complete set of five in the collection of Wordsworth's poems by English poet and critic Matthew Arnold (1822–1888).
The grouping and sequence of the "Lucy poems" has been a matter of debate in literary circles. Various critics have sought to add poems to the group; among those proposed over the years are "Alcaeus to Sappho", "Among all lovely things", "Lucy Gray", "Surprised by joy", "Tis said, that some have died for love", "Louisa", "Nutting", "Presentiments", "She was a Phantom of delight", "The Danish Boy", "The Two April Mornings", "To a Young Lady", and "Written in Very Early Youth". None of the proposals have met with widespread acceptance. The five poems included in the Lucy "canon" focus on similar themes of nature, beauty, separation and loss, and most follow the same basic ballad form. Literary scholar Mark Jones offers a general characterisation of a Lucy poem as "an untitled lyrical ballad that either mentions Lucy or is always placed with another poem that does, that either explicitly mentions her death or is susceptible of such a reading, and that is spoken by Lucy's lover."
With the exception of "A slumber", all of the poems mention Lucy by name. The decision to include this work is based in part on Wordsworth's decision to place it in close proximity to "Strange fits" and directly after "She dwelt" within Lyrical Ballads. In addition, "I travelled" was sent to the poet's childhood friend and later wife, Mary Hutchinson, with a note that said it should be "read after 'She dwelt'". Coleridge biographer J. Dykes Campbell records that Wordsworth instructed "I travelled" to be included directly following "A slumber", an arrangement that indicates a connection between the poems. Nevertheless, the question of inclusion is further complicated by Wordsworth's eventual retraction of these instructions and his omission of "I travelled" from the two subsequent editions of Lyrical Ballads.
The 1815 edition of Lyrical Ballads organised the poems into the Poems Founded on the Affections ("Strange fits", "She dwelt", and "I travelled") and Poems of the Imagination ("Three years she grew" and "A slumber"). This arrangement allowed the two dream-based poems ("Strange fits" and "A slumber") to frame the series and to represent the speaker's different sets of experiences over the course of the longer narrative. In terms of chronology, "I travelled" was written last, and thus also served as a symbolic conclusion—both emotionally and thematically—to the "Lucy poems".