According to the Canada Border Services Agency web site, US citizens need proof of citizenship plus photo ID. This could be a birth certificate plus a driver's license, a NEXUS card, or a passport (no visa required for stays less than 180 days).
What types of documents are accepted for entry into the United States via land and sea?
U.S. citizens can present a valid: U.S. Passport; Passport Card; Enhanced Driver’s License; Trusted Traveler Program card (NEXUS, SENTRI or FAST); U.S. Military identification card when traveling on official orders; U.S. Merchant Mariner document when traveling in conjunction with official maritime business; or Form I-872 American Indian Card, or (when available) Enhanced Tribal Card.
Not sure what states have compliant Enhanced DL's, but I think IL is now something like 95% complaint after some recent changes. Of course 95% is as good as 0%.
There is no mention of EDLs on the Canadian site, and Wikipedia suggests that EDLs were a passing thing good from original issue but no longer issued nor renewed.
Noo screw up, I guess I just misremembered, I thought we decided in the Virginias, but I looked, apparently we only narrowed it down to east coast. The virginias seemed to have a lot of support, you should add it to the choices.