The state of Illinois played a crucial role in the Underground Railroad, a network of secret routes and safe houses used by slaves to escape to freedom in the 19th century. Many abolitionists in Illinois provided safe houses for escaping slaves, and Chicago was a key hub on the Underground Railroad.

McHenry County, located in northeastern Illinois, has a rich history dating back centuries. Before European settlement, the area was inhabited by various Native American tribes, including the Potawatomi and Fox nations. In the early 1800s, European settlers began arriving, drawn to the region's fertile land and abundant natural resources.

In 1836, McHenry County was officially established, named after Major William McHenry, a prominent figure in the Black Hawk War. The county experienced rapid growth during the mid-19th century, fueled by the arrival of the railroad in the 1850s. Towns like McHenry, Crystal Lake, and Woodstock flourished as agricultural centers, with farming and dairy industries becoming the backbone of the local economy.

During the late 19th and early 20th centuries, McHenry County saw further development and diversification. Manufacturing industries, such as the McHenry Wagon Works and the Star Manufacturing Company, brought economic growth and employment opportunities. The county's population continued to increase, with immigrants from Germany, Poland, and other European countries settling in the area.

In the latter half of the 20th century, McHenry County experienced significant suburbanization. As nearby cities like Chicago expanded, the county became a popular residential area for those seeking a suburban lifestyle. Today, McHenry County is known for its picturesque landscapes, thriving communities, and a mix of urban and rural areas. The county's history is celebrated through its many museums, historical societies, and preservation efforts to honor its past while embracing a vibrant future.

  • 1834 - McHenry County was established on January 16, 1834.
  • 1836 - The first permanent settlement, located in Grafton Township, was established by European-American pioneers.
  • 1841 - The county seat was established in McHenry City.
  • 1843 - The first courthouse was built in McHenry City.
  • 1844 - McHenry County's first newspaper, the "McHenry County Patriot," was established in Woodstock.
  • 1872 - The present McHenry County courthouse, located in Woodstock, was completed.
  • 1940s - The county experienced significant growth and development due to the construction of several defense plants during World War II.
  • 1950s - The population of McHenry County began to rapidly increase as suburbanization from Chicago reached the area.
  • 1960 - The City of Crystal Lake, the largest city in the county, was officially incorporated.
  • 1974 - Moraine Hills State Park, located in the southeastern part of the county, was established.
  • 1990s - McHenry County became one of the fastest-growing counties in Illinois, experiencing substantial urbanization and development.
  • 2012 - The McHenry County Conservation District celebrated its 50th anniversary.