What is the importance of Ottawa, Illinois in the novel, Zorrie?

Ottawa, Illinois is one of the cities where Zorrie moves after leaving Indiana as a young woman. A few days after arriving in town, she finds work at the Radium Dial Company. She begins painting clock faces with radium, or Luna powder. She makes friends with two young women who also work at the factory, Janie and Marie. Though Zorrie loves her job and her friendships with Janie and Marie, she longs for home. Not long later, she leaves Illinois and travels back to Indiana.