American Romanticism shares some characteristics with British Romanticism, such as a preoccupation with nature, and the depths of emotion that can be stimulated by nature. We certainly see elements of the natural world in this poem, as the speaker absorbs the sense of deep stillness in the room and compares it to the stillness that occurs "between the Heaves of Storm." Another element which is extremely central to American Romanticism—far more so than British Romanticism—is individualism, or self-reliance. This can take the form of introspection, strength in solitude, and so on. In this poem, the speaker is in the process of dying, but still very much has a sense of herself which is distinct from the unnamed watchers around the bed: she feels that part of herself is "assignable"—but not all of it. There is very much an emphasis on the fact that her soul will continue beyond the physical realm—indeed, that it has done, as the first line tells us that this poem is written from a point beyond death.

"I Heard A Fly Buzz-when I died" contains several characteristics of the Romantic movement, particularly feelings of solitude and introspection.

The premise of the poem reflects on the speakers' feelings of solitude.  The opening lines emphasize the loneliness in terms of the overwhelming quiet of the setting:

"The Stillness in the Room
Was like the Stillness in the Air" (2-3).

Even in the second stanza describing the silence of the people attending the deathbed, Dickenson characterizes the watchers as desembodied parts--Eyes and Breaths.  The speaker feels little connection to them, and instead focuses on the silence, broken by the buzzing of the fly.  This poem is incredibly introspective, the final moments in death made internal through silence and the sound of a fly.