Bethalto is a village located in Madison County, Illinois, United States. Bethalto, like the rest of Madison County, is part of the Illinois Metro East portion of the Greater St. Louis metropolitan area. The population of Bethalto was 9,521 at the 2010 census.
Bethalto is located at 38°54′15″N 90°2′48″W (38.904197, -90.046579).
According to the 2010 census, Bethalto has a total area of 7.6 square miles (19.68 km2), of which 7.52 square miles (19.48 km2) (or 98.95%) is land and 0.08 square miles (0.21 km2) (or 1.05%) is water.
Bethalto was founded in 1834, incorporated April 19, 1869, under a special charter and again in 1873 under the State of Illinois' general law. It is governed by a Village President and six trustees elected at large.
The original name of Bethalto was Bethel. However, when the first post office was established, it was discovered that there was already a Bethel, Illinois. There is a general consensus that the name "Bethalto" came from the first four letters of Bethel and the first four letters of nearby Alton.
The Bethalto Village Hall is listed on the National Register of Historic Places.
As of the census of 2000, there were 9,454 people, 3,810 households, and 2,647 families residing in the village. The population density was 1,437.3 people per square mile (554.7/km2). There were 4,007 housing units at an average density of 609.2 per square mile (235.1/km2).