Oswego (pop. approx. 18,000) is a city on Lake Ontario. The area was settled in 1722. Over the next six decades the British built three successive forts, ceding the last fort to the U.S. only thirteen years after the end of the Revolutionary War. American forces erected the fourth and current fort between 1839 and 1844; since 1949, it has been a historic site and is currently being restored. Oswego, a major lake port, was once a major rail hub also. It is the home of physician and dress reformer Mary Edwards Walker, the only woman Medal of Honor recipient.