At the end of the poem, the poet concludes that his lost childhood went to some forgotten place. This conclusion is drawn based on the overall tone and theme of the poem, as well as the specific imagery and language used by the poet.

The poem explores the concept of lost childhood and the nostalgic longing for that innocence and wonder. Throughout the poem, the poet reflects on the experiences and memories of his childhood, which he feels have slipped away and are now inaccessible to him. The poet uses vivid imagery and metaphors to convey the idea of the lost childhood, describing it as "the land of lost content" and "the land where I have lost my way."

One key clue to the conclusion can be found in the line "I cannot bring them back again." This line suggests that the poet has tried to recapture his lost childhood but has been unsuccessful. It implies that the childhood has not simply shifted to another dimension or moved away with time, but rather it has been forgotten or lost in some way.

The use of the word "forgotten" in the conclusion indicates that the poet believes his childhood has been left behind, not intentionally, but rather as a result of the passage of time and the complexities of adulthood. It suggests that the memories and experiences of childhood have faded or been overshadowed by the demands and responsibilities of adulthood.

The conclusion also aligns with the overall theme of the poem, which is the bittersweet nostalgia for the simplicity and joy of childhood. The poet acknowledges that he can never fully reclaim or relive his lost childhood, and instead, it remains a distant and forgotten place.

Overall, the conclusion that the poet draws about his lost childhood being in some forgotten place is supported by the imagery, language, and theme of the poem. It conveys a sense of longing and acceptance, as the poet recognizes that his childhood is lost to him and can never be fully recovered.