Futility
Futility is a major theme in this poem. The Irish landscape lacks the potential for progress that the speaker sees in the American landscape. By comparing the pioneers of America to those who explore the Irish bogs, the speaker highlights the fact that the Irish bogs do not yield as much productivity as a land that produces coal. The speaker also seems interested in the expansiveness of the American prairies compared to the enclosed, claustrophobic feeling of the Irish landscape produced by the "enroaching horizon."
The preservation of history
In this poem, the bogs preserve remnants of history, and by digging, the people of Ireland are able to uncover them. There are also references to the cultural history of Ireland through the mention of the cyclops, a mythological creature. The speaker implies that this internal exploration of a culture's history exists instead of outward exploration—like what has happened on the American frontier—and that Ireland's preservation of history works against its progress as a nation.
The collective voice
In this poem Heaney removes any trace of himself, instead speaking from a collective voice that seems to represent the voice of the Irish people. The people of the past in this landscape seem connected to the people of the present; in the final stanza, the layers of the bogs that the present-day Irish people dig through seem "camped on" before. The preserved butter, the skeleton of the Great Irish Elk, and the cyclops emphasize how the past of Ireland still plays out in the present, and the collective voice indicates how the people of Ireland are connected as well.
