Huntsville Is A City Centrally Located In The Northernmost Part Of The U.S. State Of Alabama. It Is Located In Madison County And Extends West Into Neighboring Limestone County. Huntsville Is The County Seat Of Madison County, And The Fourth-Largest City In Alabama. The 2000 Census Estimated Huntsville'S Population At 158,216, While In 2008, The Estimated Population Grew To 176,645. The Huntsville Metropolitan Area'S Population Was Estimated At 395,645. Huntsville Is The Largest City In The Four-County Huntsville-Decatur Combined Statistical Area, Which In 2008 Had A Total Population Of 545,770. more... See more text