According to the Death Penalty Information Center, as of January 1, 2016, there were 55 women on death row. Fifteen women have been executed in the United States since 1976.
Right now, you can watch the documentary Women on Death Row for free if you have access to Netflix or Amazon Prime Video.
From IMBD:
Look into the personal lives of women currently awaiting execution on Death Row. Though each woman is convicted of committing society’s ultimate crime, there is often another side of the story.
Women on Death Row (2006)