"The Forge" is a sonnet. In the octet or first eight lines, the narrator sets the scene. The narrator peeks in through a door to a dark space. At this point, all he sees are old-fashioned objects: axles and rusting iron hoops. Then he hears the sound of a hammer hitting an anvil and sees sparks. To him, the sounds are both a ring and the "hiss" made when a "new shoe" is dunked in water to be toughened. Eventually, the narrator focuses on the anvil, which the narrator first imagines rather than sees. He envisions it in the center of the room and looking like a "horned...unicorn."

The poem "turns" to the sextet or last six lines on the word "altar," suggesting that this is one of the most important words in the poem and that the setting a sacred space. In these last six lines, the narrator imagines and describes the blacksmith as "leather aproned, hairs in his nose." It is important to note that the narrator is not capturing a particular moment in time but envisioning the blacksmith in different characteristic stances—both imagining the past world of horse's hooves when his work was more necessary and valued and when he was actually at work on his creations, grunting, slamming, beating, working the bellows. The speaker communicates that the smith is both a thinker and a doer. He captures the beauty of a craft that has almost disappeared in the modern day.