the Mormon Jail; the jail next built which was also the Sheriff's residence and is on the south side of the Courthouse square; and the new jail, on Highway 136 on the city's west side. The Hancock County Courthouse in Carthage, built in 1908, is the third courthouse for the county. It is at the center of the square in Carthage. The courthouse and shops surrounding the square have been listed on the National Register of Historic Places since 1986. Geography Carthage is located near the center of Hancock County at (40.414327, -91.133472). U.S. Route 136 runs through the center of town as Buchanan Street; it leads east to Macomb and west to Keokuk, Iowa, on the Mississippi River. Illinois Route 94 leads north from Carthage as Madison Street and east with US-136 to Illinois Route 110 just outside the city limits. Dallas City is north of Carthage via IL-94 and IL-9, while Quincy is south via IL-110. According to the 2010 census, the city has an area of , all land. In June 2006, development property on the east side of Carthage was voluntarily annexed into the city limits. This property totaled approximately , all land except for an lake. Demographics 2010 census As of the 2010 Census, there were 2,605 persons living in 1,151 households in Carthage. With an area of 2.44 square miles, the population density was 1,067 persons per square mile. There were 1,308 total housing units, with an average density of 536 per square mile. Racially, 97.3% of Carthage residents identified themselves as white, 0.3% identified as Black/African American, 0.3% were Native American, and 0.4% identified themselves as Asian. No residents identified themselves as Pacific Islander. 0.5% of the remaining population identified themselves as belonging to some other race, while 1.2% belonged to multiple races. Between all races, 2.0% of the population identified as hispanic or Latino. 2007–2011 Census data showed 19.2% of Carthage residents were under the age of 18, while 22.6% of the population was over the age of 65. The median age in Carthage was 44.0 years, and there were 88.3 males for every 100 females. Of residents over the age of 15, 50.8% of persons were married. Of persons over the age of 25, 93.2% had earned at least a high school diploma while 19.2% had earned a bachelor's degree or higher. 7.2% of persons held a graduate degree. For census