Was there a real Francesca Johnson of Madison county?

Francesca Johnson is a fictional character from Robert James Waller's novel "The Bridges of Madison County." The story, set in Madison County, Iowa, revolves around her brief but profound love affair with a traveling photographer. While the character and her experiences are not based on a real person, the novel and its film adaptation have popularized the region and its covered bridges, leading some to believe in the existence of a real Francesca. However, she remains a creation of fiction.