The film is set in 1965, featuring Italian war bride, Francesca Johnson (Meryl Streep), who lives with her husband and two children on their Iowa farm. That year she meets National Geographic photojournalist, Robert Kincaid (Eastwood), who comes to Madison County to photograph its historic covered bridges. With Francesca's family away for a short trip, the couple have an intense, four-day love affair.
In the present, adult siblings Michael and Carolyn Johnson arrive at the Iowa farmhouse of their recently deceased mother, Francesca, to settle her estate. They are shocked upon learning that Francesca requested to be cremated and her ashes scattered from Roseman Covered Bridge, rather than be buried next to her late husband, Richard.
Michael initially refuses, but while he and Carolyn look through the safe deposit box, they discover an envelope containing photographs, letters, and a key. The photos are of Francesca taken at the Holliwell Covered Bridge and the letters are from a man named Robert Kincaid. The key is to Francesca's locked hope chest. In it are three hardbound notebooks. There are also several National Geographic magazines, including one featuring Madison County's covered wooden bridges, old cameras, a book, and other mementos. The magazine includes a photo of Kincaid, who photographed the bridges; he is wearing Francesca's crucifix pendant. As Michael and Carolyn begin reading Francesca's notebooks, the film flashes back to 1965.