 mclean county is the largest county by land area in the u.s. state of illinois. according to the 2010 census, it had a population of 169,572. its county seat is bloomington. mclean county is included in the bloomington, il metropolitan statistical area. ==pronunciation== locally, the second syllable of mclean is pronounced with a 'long a' (Ä, ipa /ei/) sound (i.e. "muh-klain") (as with native son mclean stevenson), not with a 'long e' (Ä, ipa /i/) sound ("muh-kleen"). ==history== mclean county was formed late in 1830 out of tazewell county. it was named for john mclean, united states senator for illinois, who died in 1830. file:mclean_county_illinois_1830.png|mclean county from the time of its creation to 1837 file:mclean county illinois 1837.png|mclean county between 1837 and 1841 file:mclean county illinois 1841.png|mclean county in 1841, reduced to its present borders ==geography== according to the u.s. census bureau, the county has a total area of , of which  is land and  (0.2%) is water. it is the largest county in illinois by land area and third-largest by total area. mclean county is actually larger than the land area of rhode island (1045 sq mi). ===climate and weather=== {{climate chart |bloomington, illinois |14|31|1.73 |18|37|1.71 |29|48|2.87 |40|61|3.83 |51|73|4.52 |61|83|3.88 |65|86|3.95 |63|84|3.83 |54|77|2.95 |42|65|2.71 |31|49|3.06 |20|36|2.41 |float=right |units=imperial |clear=both |source=the weather channel{{cite web |url=http://www.weather.com/weather/wxclimatology/monthly/graph/usil0113 |title=monthly averages for bl
1830_establishments_in_Illinois Illinois_counties McLean_County,_Illinois Populated_places_established_in_1830