Mary Dixon Kies, the first woman to receive a patent in the U.S., did so in 1809. Kies received her patent for a process for weaving straw for bonnets. At that time, the hat industry was very important. (Read more about Kies.)
Here are some interesting and informative sites on women inventors and their patents.
To find more information on Women Inventors, try the following Google searches (use quotes to make the search more targeted.)