When missionary work first started, most organizations (or perhaps all... I haven't been able to check) sent out ordained men, and if married, their families. Single women weren't allowed to go.
Charlotte White was one of the first single women missionaries... she helped to carve the way for my friends today who are out of the mission field.
I know she was single, she married shortly after she got to the mission field. This was back in 1815.
She sounded like an interesting woman. Widowed. Insisted on being sent to India and bribed her way there by donating land to the mission agency! (source)
She had to pay her own way. (source)
She was sent out only as a helper, not as a missionary in her own right. She was a helper to Henry Hough.
She believed her life was a set of trials and they won't stop just because she was on the mission field (source)
Her husband, Joshua Rowe, was a widower with three sons who died a few years after their marriage. He worked with a different mission agency, and after they married, They married in 1816. Charlotte transferred to that agency. Together they had three children. Mr. Rowe died in 1823. She stayed in India for three years after his death before returning to the states with the children in 1826.
The work the Rowe's did in India was to manage mission schools. Charlotte wrote a Hindustani language primer for children. (source)
Those Good Gertrudes.
Center for Baptist Studies.