What is the importance of Randall's Island in the novel, Odds Against Tomorrow?

Randall’s Island is an area of high ground just outside of New York City, which becomes a place of sanctuary for Mitchell, Jane, and other refugees from New York after it has been flooded. The island is a place where they and the others simultaneously recover from what has happened and work out ways to move forward. Over time, the space becomes increasingly populated and increasingly ungovernable.