The first mention of the poems came from Dorothy, in a letter sent to Coleridge in December 1798. Of "Strange fits", she wrote, "[this] next poem is a favorite of mine—i.e. of me Dorothy—". The first recorded mention of any of the "Lucy poems" (outside of notes by either William or Dorothy) occurred after the April 1799 death of Coleridge's son Berkeley. Coleridge was then living in Germany, and received the news through a letter from his friend Thomas Poole, who in his condolences mentioned Wordsworth's "A slumber":
But I cannot truly say that I grieve—I am perplexed—I am sad—and a little thing, a very trifle would make me weep; but for the death of the Baby I have not wept!—Oh! this strange, strange, strange Scene-shifter, Death! that giddies one with insecurity, & so unsubstantiates the living Things that one has grasped and handled!—/ Some months ago Wordsworth transmitted to me a most sublime Epitaph / whether it had any reality, I cannot say.—Most probably, in some gloomier moment he had fancied the moment in which his sister might die.
Later, the essayist Charles Lamb (1775–1834) wrote to Wordsworth in 1801 to say that "She dwelt" was one of his favourites from Lyrical Ballads. Likewise Romantic poet John Keats (1795–1821) praised the poem. To the diarist and writer Henry Crabb Robinson (1775–1867), "She dwelt" gave "the powerful effect of the loss of a very obscure object upon one tenderly attached to it—the opposition between the apparent strength of the passion and the insignificance of the object is delightfully conceived."
Besides word of mouth and opinions in letters, there were only a few published contemporary reviews. The writer and journalist John Stoddart (1773–1856), in a review of Lyrical Ballads, described "Strange fits" and "She dwelt" as "the most singular specimens of unpretending, yet irresistible pathos". An anonymous review of Poems in Two Volumes in 1807 had a less positive opinion about "I travell'd": "Another string of flat lines about Lucy is succeeded by an ode to Duty". Critic Francis Jeffrey (1773–1850) claimed that, in "Strange fits", "Mr Wordsworth, however, has thought fit to compose a piece, illustrating this copious subject by one single thought. A lover trots away to see his mistress one fine evening, staring all the way at the moon: when he comes to her door, 'O mercy! to myself I cried, / If Lucy should be dead!' And there the poem ends!" On "A slumber did my spirit seal", Wordsworth's friend Thomas Powell wrote that the poem "stands by itself, and is without title prefixed, yet we are to know, from the penetration of Mr. Wordsworth's admirers, that it is a sequel to the other deep poems that precede it, and is about one Lucy, who is dead. From the table of contents, however, we are informed by the author that it is about 'A Slumber;' for this is the actual title which he has condescended to give it, to put us out of pain as to what it is about."
Many Victorian critics appreciated the emotion of the "Lucy poems" and focused on "Strange fits". John Wilson, a personal friend of both Wordsworth and Coleridge, described the poem in 1842 as "powerfully pathetic". In 1849, critic Rev. Francis Jacox, writing under the pseudonym "Parson Frank", remarked that "Strange fits" contained "true pathos. We are moved to our soul's centre by sorrow expressed as that is; for, without periphrasis or wordy anguish, without circumlocution of officious and obtrusive, and therefore, artificial grief; the mourner gives sorrow words... But he does it in words as few as may be: how intense their beauty!" A few years later, John Wright, an early Wordsworth commentator, described the contemporary perception that "Strange fits" had a "deep but subdued and 'silent fervour'". Other reviewers emphasised the importance of "She dwelt among the untrodden ways", including Scottish writer William Angus Knight (1836–1916), when he described the poem as an "incomparable twelve lines".
At the beginning of the 20th century, literary critic David Rannie praised the poems as a whole: "that strange little lovely group, which breathe a passion unfamiliar to Wordsworth, and about which he—so ready to talk about the genesis of his poems—has told us nothing [...] Let a poet keep some of his secrets: we need not grudge him the privacy when the poetry is as beautiful as this; when there is such celebration of girlhood, love, and death [...] The poet's sense of loss is sublime in its utter simplicity. He finds harmony rather than harshness in the contrast between the illusion of love and the fact of death." Later critics focused on the importance of the poems to Wordsworth's poetic technique. Durrant argued that "The four 'Lucy' poems which appeared in the 1800 edition of Lyrical Ballads are worth careful attention, because they represent the clearest examples of the success of Wordsworth's experiment." Alan Grob (1932–2007) focused less on the unity that the poems represent and believed that "the principal importance of the 'Matthew' and 'Lucy' poems, apart from their intrinsic achievement, substantial as that is, is in suggesting the presence of seeds of discontent even in a period of seemingly assured faith that makes the sequence of developments in the history of Wordsworth's thought a more orderly, evolving pattern than the chronological leaps between stages would seem to imply."
Later critics de-emphasised the significance of the poems in Wordsworth's artistic development. Hunter Davies (b. 1936) concluded that their impact relies more on their popularity than importance to Wordsworth's poetic career. Davies went on to claim, "The poems about Lucy are perhaps Wordsworth's best-known work which he did in Germany, along with 'Nutting' and the Matthew poems, but the most important work was the beginning of The Prelude" (emphasis in original). Some critics emphasised the importance behind Lucy as a figure, including Geoffrey Hartman (b. 1929), when he claimed, "It is in the Lucy poems that the notion of spirit of place, and particularly English spirit of place, reaches its purest form." Writer and poet Meena Alexander (b. 1951) believed that the character of Lucy "is the impossible object of the poet's desire, an iconic representation of the Romantic feminine."