The town of Derby Line straddles the US/Canada border. The border passes right through the town, even through some buildings and homes. In some cases, a family at home cooks its meals in one country and eats them in the other. Derby Line is also home to the Haskell Free Library and Opera House, which was purposely built on the border. The opera stage is in Canada, but the entrance to the opera, and most of the stage seats, are in the United States. Because the building straddles the border, it has two mailing addresses, one for the US and one for Canada.