Three wondrous female folk musicians that I've spent a lot of time learning their songs, and listening to their tunes are:
Alela Diane, Jessica Lea Mayfield, and Eilen Jewell.
Jessica Lea Mayfield is pretty pop now, unfortunately.. but, she put out a couple good folk albums in the beginning of her career.
Also, PROFANE SASS
Fellow travellers that are SO underrated, surprisingly. Can't believe I haven't seen their name on this list yet.. Unfortunately, their mandolin player passed, due to a train accident.