There is a variety of documentation that could be used at a land border crossing, including an enhanced driver's licence. The majority do use a passport; that's usually what's used. Or, you could also use a NEXUS card if you're in a NEXUS lane. There is a series of acceptable documentation at the land port of entry, but at the very least, what is expected is that documentation is presented, and that is recorded into the system.
On May 29th, 2017. See this statement in context.