McHenry County, Illinois, is located along the northern border of the state, separated from Lake Michigan only by Lake County, to the east. Counties bordering McHenry are Kane and Dekalb to the south, and Boone to the West. Cross the southeast corner and you are in Cook County.
     The County was formed  in 1836, of  the entire northern half of the original Cook County. In 1839 the land area of McHenry County was further diminished by the splitting off of the eastern part now known as Lake County. It was named for Major William McHenry, of White County, Illinois, famous commander in  the Black Hawk War. (He is not related to James McHenry, Secretary of War under George Washington, for whom Fort McHenry is named.)
 

ILLINOIS IN 1837
"A Sketch Descriptive of the
Situation, Boundaries, Face of the Country,
Prominent Districts,
Prairies, Rivers, Minerals, Animals,
Agricultural Productions,
Public Lands, Plans of Internal Improvement,
Manufactures, &c.
of the State of Illinois"....
"Sketches of the Counties, Cities, and Principal Towns in the State"
 (pages 89 & 90)

MCHENRY County occupies the north-eastern corner of the state, and is bounded on the north by Walworth and Racine counties of Wisconsin Territory, south by Cook and Kane counties, east by lake Michigan, and west by Boone county. It contains an area of about 1100 square miles, and is in extent from east to west from 47 to 42 miles, and from north to south 24.  It is watered by the Fox, DesPlaines, and Chicago rivers and their branches, together with several small lakes, of which some have limpid waters in gravelly beds, with ridges of gravel and sand around them.  Groves of fine timber are found along the lake shores and on the banks of the streams, and also distributed through the prairies.  The county is well watered, the streams perennial, and the soil rich and covered with luxuriant herbage. The county is filling up rapidly with an enterprizing population, now estimated at from 1000 to 1200 souls. The seat of justice is not yet located. The only town in the county is M'Henry, situated on the west side of the Fox river, and about 12 miles south of the northern boundary of the state. It is surounded with excellent prairie and timber in groves, and oak openings or barrens.

First County Settlers

    The first settlers began arriving in this area in 1834, and could have been said to be stealing land from the Indians, as the treaty that gave the Indians control of the land was still in effect until 1836.
"By law of congress settlers were forbidden to occupy the newly ceded Indian lands before the year 1836. This provision of the law, like most, did not result in actual prohibition. A few bold pioneers, anxious to test the quality of the soil of the new country, longing for the wild freedom of life on the broad prairies, pushed their way into the region west of Lake Michigan, and the year 1835 witnessed the advent of several white settlers to the present counties of McHenry and Lake." McHenry County History, 1885
    The first white settlers of the county were the Samuel Gillilan family, arriving September 18, 1834. They settled in the area that is now Camp Algonquin, between the towns of present day Algonquin and Cary. Samuel's brother John Gillilan followed in 1835. By 1835, the Virginia Settlement (Crystal Lake, Dorr Township), was populated with the likes of James Dufield, Christopher Walkup, John Walkup, Josiah Walkup, William Hartman, John Gibson, John McClure, and the Samuel Gillilan family. The other main settlement of 1835, dubbed the "first community" of the County, was Pleasant Grove, now Marengo. Settlers there were: Oliver Chatfield, Calvin Spencer, AB Coon, Porter Chatfield, Russell Diggins, Richard Simpkins, and Moody B. Bailey.
   The earliest settlers migrated mainly from New York, New England, and Virginia (hence, Virginia Settlement). Hartland township was primarily settled by Irish Catholics, and German settlers later came to the county, settling in Johnsburg, McHenry, as well as other towns.

The Old Settlers Association of McHenry and Lake Counties

Population Boom