Delaney is a self-proclaimed liberal humanist and nature writer who recently moved from New York to the upper-middle-class Arroyo Blanco Estates in Southern California. He writes a column called "Pilgrim at Topanga Creek" and handles the domestic duties while his wife works. He tries to reconcile his progressive ideals with his growing fear and resentment after the car accident.

Kyra is a highly successful, driven real estate agent who serves as the chief breadwinner for her family. She is deeply invested in her career, managing 46 listings across the region. She frequently worries about property values and neighborhood security, pushing for physical barriers to protect her community.

Cándido is a 33-year-old undocumented Mexican immigrant camping at the bottom of the canyon. A hardworking and traditional man, he feels a deep responsibility to provide for his young, pregnant wife. His severe injuries from the car accident leave him temporarily disabled, forcing him to adapt to an increasingly hostile environment.

América is Cándido's 17-year-old pregnant wife. She left a secure childhood in Mexico under the promise of a better life. Forced into the harsh reality of living in a ravine, she takes it upon herself to seek work at the labor exchange when Cándido is injured.

José Navidad is a racially ambiguous, Spanish-speaking man who wanders the canyon area wearing a backward baseball cap and carrying a bedroll. He presents a threatening presence to nearly every major character in the novel, inflicting actual violence on the most vulnerable residents of the ravine.

Jordan is Kyra's son and Delaney's stepson. He lives in Arroyo Blanco Estates and eats a strictly controlled diet dictated by his mother. His daily routine is mostly managed by Delaney due to Kyra's demanding work schedule.

Jack is a lawyer and the Mossbachers' neighbor in Arroyo Blanco Estates. He is an outspoken advocate for building a gate and wall around the community. He frequently expresses conservative, anti-immigrant viewpoints that challenge Delaney's self-image.

Jack Jr. is the gangly 18-year-old son of Jack Jardine. He roams the canyon and neighborhood with his friends. He expresses bigoted views about immigrants and engages in vandalism against the vulnerable people living in the ravine.

Jim Shirley is a wealthy resident of Arroyo Blanco who frequently hires undocumented labor despite the community's exclusionary politics. He is a demanding employer who provides unsafe working conditions. He acts inappropriately toward vulnerable female workers at his home.

Mary is a white American woman who frequents the labor exchange looking for day jobs. Her presence shocks América, who cannot believe a citizen would compete for the same grueling, low-paying work.

Dominick Flood is a wealthy Arroyo Blanco resident serving a three-year house arrest sentence for illegal banking investments. Despite his status as a convicted criminal, he remains a respected, cheerful member of the community who supports removing the labor exchange.

Kit is Kyra's mother. She participates in the social life of Arroyo Blanco and mingles with the affluent neighbors during holiday gatherings.

Candelario is the headman who manages the labor exchange in the supermarket parking lot. He organizes the workers and negotiates with the American employers who drive up seeking cheap day labor.

Señor Willis is an older, alcoholic man who occasionally hires Cándido for construction projects. He provides a brief period of financial stability for the Rincóns before disappearing and reappearing sporadically.

Todd Sweet is a resident of Arroyo Blanco who actively opposes the construction of the community wall. He approaches Delaney hoping to find a liberal ally against the neighborhood's exclusionary politics.