Set on a farm in Iowa, A Thousand Acres draws on William Shakespeare’s King Lear (c.1605) in its story of an aging farmer who decides to divide his land among his three daughters. His decision alters the family’s life forever and forces his oldest daughter, Ginny, the book’s narrator, to confront her past.

The story opens in 1979 in Zebulon County, Iowa, as Larry Cook announces his decision to split his land among his children. Cook’s married daughters and their husbands agree to the plan, but his youngest daughter, Caroline, who has left the farm and is now an attorney, voices her disapproval and is cut out of the arrangement by her father. The plan unfolds quickly, and though Ginny herself has misgivings about it, Cook is a domineering man whose family rarely challenges him.

For Ginny’s husband, Ty Smith, a hardworking man who has treated his father-in-law with respect and patience, the agreement offers a chance to undertake a hog-farming project of which he has long dreamed. Ginny and Ty have been unable to have children—Ginny has suffered five miscarriages, only three of which she has revealed to her husband—yet their marriage is placid, steady, and comfortable. Rose and Pete’s relation is less successful—he drinks and is sometimes abusive—but they have two daughters, Pammy and Linda.

Larry Cook’s decision coincides with the return of Jess Clark, the son of Cook’s neighbor and friend, Harold Clark. Jess has not been home since he fled to Canada during the Vietnam War, and his return is an event in the small community. His brother, Loren, has remained at home with his father on the family farm. Ginny is immediately drawn to Jess, who has lived the unsettled life of a drifter and returned with unfamiliar habits and ideas. The two eventually become lovers, as Ginny begins to grow dissatisfied with Ty.

Soon after his land has been divided between Ginny and Rose, Larry’s actions become increasingly erratic and give rise to considerable tension within the family. The two sisters decide to be firm with their father and set rules for his behavior, which leads him to seek out Caroline and repair his rift with her. During a violent thunderstorm, Larry refuses to come indoors and later tells Harold Clark that his daughters turned him out of the house. As the storm rages, Rose confronts Ginny with the truth about their childhood, truth that Ginny has long since repressed; following their mother’s death when they were teenagers, their father had sexually abused both girls.

At a church dinner, Harold Clark denounces Ginny and Rose and what he perceives as their mistreatment of their father, who is now living with the Clarks. He also turns on Jess, whom he had seemed to favor over Loren, claiming that Jess is plotting to gain control of the farm. Several days later, Harold is blinded while treating his fields with anhydrous ammonia. Ginny and Rose also learn that Caroline is suing them on behalf of their father in an attempt to regain control of the farm, and Ginny discovers that Ty has provided Caroline with information about the night of the storm. Ty also learns the truth about Ginny’s miscarriages, and the gulf between them widens.

Following a drunken quarrel with Harold, Rose’s husband Pete drowns in the local quarry, a possible suicide, and Rose confesses to Ginny that she, too, is having an affair with Jess. When Ginny learns that it is Rose whom Jess loves and that her sister knows of their affair, she conceives a plan to poison Rose with a jar of homemade sausages, which Rose puts aside and never eats. The lawsuit brought by Caroline is settled in favor of Ginny and Rose, and Ginny takes a thousand dollars from Ty and leaves the farm.

She settles in St. Paul, where she finds work as a waitress. When she at last contacts Rose several months later, she learns that their father died of a heart attack shortly after the lawsuit was concluded. Several years pass before Ty appears suddenly one day with the news that his portion of the farm has failed; he announces that he is moving to Texas and would like a divorce. The following spring, Rose, who has since broken up with Jess, suffers a recurrence of breast cancer, from which she will not recover, and she asks Ginny to take her daughters. While sorting through items in the farmhouse with Caroline before it is auctioned off, Ginny considers confronting her sister with their father’s sexual abuse, but ultimately says nothing. She returns to St. Paul and builds a life with her nieces.