The website Ask Art has a list of noteworthy American, women artists, including a number of painters. Wikipedia has a more exhaustive list of around 650 painters. Both websites link to biographies and examples of the artists' work from the lists.
The Ask Art list of artists is in the form of a short article, placing the most notable artists in historical context and briefly discussing why their work is significant. The list includes female sculptors, illustrators and mixed-media artists as well as painters. By contrast, the Wikipedia list does not offer any such context on the page that lists the artists. However, each artist's name links to a page with biographical material. The Wikipedia list is also limited to female artists who paint at least part of the time.