McHenry lies within the Fox River Valley, and its downtown area is situated on that river which is how it earned the nickname 'The Heart of the Fox River'. McHenry is located 50 miles northwest of Chicago in northeastern Illinois on the Fox River. In 1985, the McHenry Plaindealer became part of the Northwest Herald. One part sits on the grounds of TC Industries in Crystal Lake. The bridge was split into multiple parts and relocated. The original Pearl Street bridge was dismantled in 1976 and rebuilt using concrete. In 1929, Mill Pond was drained by removing the dam on Boone Creek.

On Maa train bound for Ringwood crashed near the McHenry train depot. In 1880, the first bridge in McHenry was built at Pearl Street. On August 4, 1875, the first issue of the city newspaper, the McHenry Plaindealer, was published by Jay Van Slyke. In 1860, the historical Count's House was completed. The pond encompassed an area between today's rail road tracks and Route 31 and north of Waukegan Road. In 1851, a dam was built on Boone Creek which created Mill Pond. Gagetown was eventually renamed to West McHenry.

In 1854, George Gage played an instrumental role in bringing the railroad to the city. This area eventually came to be known as Gagetown. George Gage came to the area in 1835 and purchased a plot of land west of the Fox River. Some of the family names can still be seen today: McCullom, McLean, Boone, and Wheeler. In the 1830s various settlers arrived in the area and created the foundation for McHenry. Moraine Hills State Park, Glacial Park Conservation Area, and Volo Bog State Natural Area preserve some of these natural features. It is surrounded by natural lakes and streams, grassy moraine hills, gravel banks and shallow nutrient-rich peat bogs, remnants of receding glaciers from the last ice age. It rests at an elevation of 797 feet and the Fox River flows through the eastern portion of the city. McHenry took its name from the county, which was named for Major William McHenry, a prominent US Army officer in the Black Hawk War. McHenry was at one time the county seat of McHenry County, which once included adjoining Lake County to the east. Per the 2020 census, the population was 27,135. It is a suburb, part of the Chicago metropolitan area and is located about 50 miles northwest of Chicago. McHenry is a city in McHenry County, Illinois, United States.

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