According to the US border crossing website, you only need one approved item to establish identity.
Starting June 1, 2009, U.S. citizens returning home from Canada, Mexico, the Caribbean or Bermuda, by land or sea, are required to present one of the travel documents listed below.
U.S. Passport – This is an internationally recognized travel document that verifies a person’s identity and nationality. It is accepted for travel by air, land and sea.
U.S. Passport Card – This is a new, limited-use travel document that fits in your wallet and costs less than a
U.S. Passport. It is only valid for travel by land and sea.
Enhanced Driver’s License (EDL) – Several states
and Canadian provinces are issuing this driver’s license
or identification document that denotes identity and citizenship. It is specifically designed for cross-border travel into the U.S. by land or sea.
Trusted Traveler Program Cards – Global Entry, NEXUS, SENTRI or FAST enrollment cards can speed your entry into the U.S. and are issued only to pre-approved, low-risk travelers. The cards are valid for use at land or sea; the NEXUS card can be used in airports with a NEXUS kiosk.
Special Groups – Information for Children, Groups of Children, Native Americans, “Closed Loop” Cruises, U.S. Lawful Permanent Residents, U.S. Military, Merchant Mariners, Ferries and Small Boats, and Boaters.
Knowing what documents are required and having them ready when you return home will help streamline the entry process and ensure your return to the U.S. is as smooth