I'm always happy to find dance ephemera from my home state of Connecticut, and this dance card is particularly local: it's from a 1910 Junior-Senior Dance at West Haven High School, whose current incarnation is less than ten miles away. Today is the last day of classes for WHHS, though I don't think it's in the same building as in 1910. In celebration, let's talk about what the students there were up to 104 years ago.
West Haven was settled in 1648 and was the landing site for a British attack during the Revolutionary War. In 1910, it was not yet an independent town but a part of neighboring Orange. The "Informal" Junior and Senior Dance for the classes of 1910 and 1911 took place on Friday, June 17th, 1910 at West Haven Town Hall.
This is a used card, with the last names of partners scrawled in pencil next to most of the dances. I would have guessed this to be a girl's card since there are only last names with no "Miss" attached to them. However, the name "Arthur" is written above the dance list; possibly this is the card owner's name.