The theme of isolation is central to Ethan Frome, shaping the characters' lives and the narrative's tone. The harsh winter setting underscores the emotional and physical isolation experienced by the characters. Ethan's decisions, driven by duty and societal expectations, lead to tragic consequences, highlighting the conflict between personal desires and moral obligations. The novel explores how isolation, both self-imposed and environmental, impacts human lives.

The setting of Starkfield, a small New England town, is significant in emphasizing isolation. The town's name itself suggests barrenness, reflecting the bleakness of Ethan's life. The rural landscape, with its harsh winters, isolates the characters physically and emotionally. The Frome farm is stark and unwelcoming, mirroring Ethan's entrapment in a loveless marriage and a life devoid of fulfillment. The winter setting further isolates the characters, making escape seem impossible.

Isolation is also evident in Ethan's personal life. His marriage to Zeena is a result of his fear of facing the winter alone. This impulsive decision traps him in a life of duty and repression. Ethan's longing for Mattie Silver represents a desire for connection and escape from isolation, but societal expectations and his sense of duty prevent him from pursuing this desire. The failed suicide attempt with Mattie symbolizes the ultimate entrapment in isolation, as they are left to live a "quietly miserable existence" together.

Ethan "seemed a part of the mute melancholy landscape, an incarnation of its frozen woe, with all that was warm and sentient in him fast bound below the surface... [living] in a depth of moral isolation too remote for casual access."

The natural environment in Ethan Frome is a metaphor for Ethan's life. The winter landscape, with its coldness and sterility, reflects Ethan's emotional state. The "mute melancholy landscape" mirrors his "moral isolation," emphasizing his inability to escape his circumstances. The isolation is not just physical but also emotional, as Ethan is unable to connect with others or pursue his own desires.

He was too young, too strong, too full of the sap of living, to submit so easily to the destruction of his hopes. Must he wear out all his years at the side of a bitter querulous woman?

Ethan's isolation is compounded by his repression. His inability to live authentically and pursue his own path leads to resentment and bitterness. The novel suggests that living a life of duty and repression results in isolation and unfulfilled potential. Ethan's story serves as a cautionary tale about the dangers of sacrificing personal fulfillment for societal expectations, leading to a life of isolation and regret.