Cairo is located in southern Illinois in Alexander County (of which it is the county seat) south of Mt. Vernon between Mound City and the confluence of the Mississippi River and the Ohio River. An obviously strategic vantage point led to the construction of Fort Defiance on the peninsula. General U.S. Grant made his early Civil War headquarters here.<br> The city is the southern most in Illinois and is part of the "Little Egypt" area. The area came to be called this from being able to provide northern and central Illinois farmers enough grain to survive the harsh winter of 1830-31. The farmers were said to be, just as Jacob's sons in the Bible, "going down to Egypt to obtain some grain".<br> Area recreation includes family outings to St. Mary's Park. The population estimate for July 1, 1998 was 4,217, a decrease of 629 since 1990.