Hancock County was part of the "Military Tract" set aside by Congress to reward veterans of the War of 1812. Actual settlement of the interior of the county was delayed by concerns about hostile American Indians. After their defeat in the Blackhawk War in 1832, settlement proceeded quickly. Hancock County was formed, on January 13, 1825, out of Pike County. It was named in honor of John Hancock, who signed the Declaration of Independence. For a brief period in the 1840s Hancock had one of Illinois' most populous cities: Nauvoo, which was then headquarters for the Church of Jesus Christ of Latter Day Saints. The movement's founderJoseph Smith was killed in the county seat of Carthage in 1844. Most Mormons left Hancock County in the 1840s. Today, Latter Day Saints come in increasing numbers to important Latter Day Saint sites in Hancock County, partly for vacation and partly for religious pilgrimage. The original courthouse was at Montebello. Montebello no longer exists but was between Nauvoo and Hamilton. In 1833 the state commissioned the formation of the county seat at Carthage, which was centrally located but not well developed. A log cabin was built to serve as the courthouse and served that purpose until 1839 when the second Carthage Courthouse was built. The original log cabin continued to serve as a school and other purposes until 1945 when it was removed. The second courthouse cost $3,700 to build and served from 1839 until 1906. It served as a location for Stephen A. Douglas and Abraham Lincoln to speak to residents as they were running against each other for the US Senate. In 1906 it was removed to make room for the current courthouse. The current courthouse was dedicated October 21, 1908.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is water.
Climate and weather
In recent years, average temperatures in the county seat of Carthage have ranged from a low of in January to a high of in July, although a record low of was recorded in February 1905 and a record high of was recorded in August 1934. Average monthly precipitation ranged from in January to in May.
As of the 2010 United States Census, there were 19,104 people, 8,040 households, and 5,427 families residing in the county. The population density was. There were 9,274 housing units at an average density of. The racial makeup of the county was 98.0% white, 0.3% black or African American, 0.2% Asian, 0.2% American Indian, 0.1% Pacific islander, 0.3% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 1.0% of the population. In terms of ancestry, 34.7% were German, 13.8% were English, 13.2% were American, and 12.1% were Irish. Of the 8,040 households, 27.5% had children under the age of 18 living with them, 55.3% were married couples living together, 8.3% had a female householder with no husband present, 32.5% were non-families, and 28.2% of all households were made up of individuals. The average household size was 2.35 and the average family size was 2.85. The median age was 44.6 years. The median income for a household in the county was $42,857 and the median income for a family was $55,162. Males had a median income of $41,609 versus $27,648 for females. The per capita income for the county was $22,885. About 8.9% of families and 12.6% of the population were below the poverty line, including 17.8% of those under age 18 and 9.9% of those age 65 or over.
