The thirteen original colonies plus Vermont and Louisiana had issues of colony or state backed currency that circulated at a discount within the colonies. From 1690 when Massachusetts (home of Denly's Hooray!) first issued currency until the late 1780's, colony and state emissions were printed and circulated. This is probably the least collected of US Currency mostly because it exists in very limited quantities.
This reference (just released Oct. 2011), designed for the specialist and dealer, offers the most complete data to be found anywhere for small-size currency, organized and listed by specific series, including accurate population figures for each. The book also contains detailed tutorial information. Most up-to-date census for all U.S. small-size currency.