The Identicals uses the distinct cultural identities of Martha’s Vineyard and Nantucket to explore the power of place in shaping one’s sense of self, positing that identity is profoundly influenced by one’s community and environment. The narrative personifies each island’s community as a collective third-person narrator to establish their separate identities, framing them as siblings with a competitive spirit. Hilderbrand uses visual imagery and sensory details to emphasize the distinct personas of the islands. Nantucket’s narrator describes “the peppermint stick of Sankaty Head Lighthouse” (6), the bar where “one can hear Grace Potter one week and Trombone Shorty the next” (6), and the “seared scallop taco with red cabbage slaw from Millie’s” (6). Similarly, Martha’s Vineyard’s narrator notes its “colorful gingerbread houses [and] dozens of family farms that harvest an abundance of organic produce” (7).

The contrast Hilderbrand draws between “gritty” Martha’s Vineyard and “stately” Nantucket directly mirrors the personalities of her twin protagonists. Harper, a resident of the Vineyard, leads a messy, unstructured life, while Tabitha, on Nantucket, adheres to the rigid, high-society expectations set by her mother. This division was cemented by their parents’ divorce, when Billy and Eleanor effectively split the islands between them, predetermining the environments that would forge their daughters’ identities. Just as the islands are outwardly similar but inwardly individual, the identical twins look the same but possess fundamentally different identities, shaped by the distinct sociocultural ecosystems they inhabit. The islands’ rivalry thus serves as a metaphor for the sisters’ interpersonal conflict.

Hilderbrand uses the island swap to illustrate that one’s sense of self is, in part, constructed in relation to one’s surroundings. Leaving their individual contexts challenges the sisters to examine their history, compelling them to confront aspects of themselves they have never examined. Inhabiting each other’s spaces allows them to see themselves and each other more clearly: Harper must adapt to the refined, moneyed world of Eleanor’s boutique on Nantucket, a stark contrast to her transient jobs waitressing and delivering packages on the Vineyard. Meanwhile, Tabitha must manage the renovation of Billy’s ramshackle house, a hands-on project far removed from her curated Nantucket life. As Harper prepares to have dinner with Ramsay, the narrator notes: “It’s her first time going out on Nantucket. She’s a different person here. She wants to dress like it” (270). She chooses clothing from the ERF boutique, where Tabitha gets her wardrobe. By removing the sisters from their comfortable contexts, the novel demonstrates that stepping into an unfamiliar place facilitates the kind of self-reflection that leads to personal growth and understanding.