Revolutionary War Spy Letters

Step into the world of secret agents and coded messages with the William L. Clements Library! Families are invited to explore real “spy letters” from the American Revolution and see how people shared information in plain sight—without anyone else realizing.

You’ll discover clever techniques used to hide messages, from invisible ink and secret codes to “mask” letters that reveal a hidden note only when you know where to look. Then it’s your turn: create your very own spy letter to take home—write in invisible ink, design a coded message, try a mask-letter overlay, or even tuck a tiny message into your quill for safekeeping.

We’ll also have facsimiles on display featuring examples from the Clements collections, so you can see how Revolutionary-era spies and messengers did it for real. Come ready to experiment, decode, and send a secret message of your own!