|Mary Agnes Chase - photo found on Buzzfeed|
There are plenty to check out - look at them all on the Buzzfeed post.
I like Mary Agnes Chase the best because people were like, "We won't fund your research! You're a woman! That is terrible!" and she was like, "Fine, I'll fund my own." (Of course, I assume she was of some form of independent means to be able to do this, but maybe she held a car wash.)
Also cool: Roger Arliner Young was the first African American woman to receive a doctorate in zoology. Botanist Matilda Moldenhauer Brooks discovered the antidote for carbon monoxide poisoning. Florence Barbara Seibert discovered the skin test for TB.