Adair is an unincorporated census-designated place

Census-designated place

A census-designated place is a concentration of population identified by the United States Census Bureau for statistical purposes. CDPs are delineated for each decennial census as the statistical counterparts of incorporated places such as cities, towns and villages...

 in McDonough County, Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. Adair is part of the New Salem Township

New Salem Township, McDonough County, Illinois

New Salem Township is located in McDonough County, Illinois. The population was 412 at the 2000 census. It is Township 5 North, Range 1 West of the Fourth Principal Meridian.- External links :***...

. The town is served by U.S. Route 136, and the Chicago, Burlington and Quincy Railroad

Chicago, Burlington and Quincy Railroad

The Chicago, Burlington and Quincy Railroad was a railroad that operated in the Midwestern United States. Commonly referred to as the Burlington or as the Q, the Burlington Route served a large area, including extensive trackage in the states of Colorado, Illinois, Iowa, Kentucky, Missouri,...

runs through the town. Adair was laid out in August 1870 under the name of Reedyville; though the name has never been officially changed, the location is known as Adair because that name was given to the post office. Adair has a population of 210 as of 2010.