Saunders Mac Lane
Mathematician
Mathematician who won the National Medal of Science for pioneering category theory, transforming previously abstract ideas into practical equations. His 1971 textbook Categories for the Working Mathematician, remains a seminal piece of work on category theory.
After graduation from Yale, and for a time worked in academia in Germany, moving back to the U.S. in 1933 with the rise of the Nazis.
His papers were widely considered to be among the most influential to 20th century mathematics and because of this he was elected to the National Academy of Sciences in 1949, and received the National Medal of Science in 1989.
He grew up in Taftville, Connecticut, both his father and grandfather ministers.
Benjamin Peirce was another well-known American mathematician who helped shaped American science for generation after him.