 greene county is a county located in the u.s. state of illinois. according to the 2010 census, it has a population of 13,886. its county seat is carrollton. it has a notable archaeological area known as the koster site, at which evidence of more than 7,000 years of human habitation has been excavated. exhibits of artifacts from the site are displayed at the center for american archeology in kampsville, illinois. ==history== greene county is named in honor of general nathanael greene, a hero of the revolutionary war. file:greene county illinois 1821.png|greene county from its creation in 1821 to 1823, including unorganized territory temporarily attached to it.white, jesse. origin and evolution of illinois counties. state of illinois, march 2010.  file:greene county illinois 1823.png|greene county between 1823 and 1825 file:greene county illinois 1825.png|greene between 1825 and 1829 file:greene county illinois 1829.png|greene between 1829 and 1839 file:greene county illinois 1839.png|greene in 1839, when the creation of jersey county reduced it to its current size ==geography== according to the u.s. census bureau, the county has a total area of , of which  is land and  (0.6%) is water. ===climate and weather=== {{climate chart |carrollton, illinois |16|34|1.60 |20|40|1.75 |30|52|3.28 |42|64|3.55 |52|74|4.34 |61|83|3.56 |65|87|3.37 |63|85|2.84 |54|78|2.96 |43|67|2.62 |32|52|3.25 |21|39|2.57 |float=right |units=imperial |clear=both |source=the weather channel{{cite web |url=http://www.weather.com/weather/wxclimatology/monthly/g
1821_establishments_in_Illinois Greene_County,_Illinois Illinois_counties Populated_places_established_in_1821