Madison is a city located primarily in Madison County, near the northern border of the U.S. state of Alabama. Madison extends west into neighboring Limestone County. The city is included in the Huntsville Metropolitan Area, the second-largest in the state, and is also included in the merged Huntsville-Decatur Combined Statistical Area. The population was 56,933 at the 2020 census. Madison is bordered by Huntsville on nearly all sides with some small unincorporated lands within Madison in Madison and Limestone counties.

Madison was mostly a small city for many years, with its population being around 400-500 for much of its history until the Redstone Arsenal was established to the southeast, which attracted many people to the area for jobs. This rapidly increased the city's population and stimulated economic growth. Many of Madison's residents work in Research Park or the Redstone Arsenal. Madison has been one of the fastest-growing cities in Alabama, as well as one of the wealthiest in the state. In 2022 census estimates, Madison was the 9th largest city in Alabama and the second largest city in North Alabama trailing only nearby Huntsville.