Markham is a city and a south suburb of Chicago in Cook County, Illinois, United States. The population was 11,661 at the 2020 census. Geography Markham is located at (41.597467, -87.691570). According to the 2021 census gazetteer files, Markham has a total area of , all land. History It is claimed this area was beach 10,000 years ago. After countless ages of geologic swamps, marshes and sloughs, the prairies dominated the landscape with groves of trees, flowers, and wildlife in abundance. Markham, southwest of the southern tip of Lake Michigan, had been a crossroad for early pioneers. In 1816 a treaty was made with the Ottawa, Chippewa and Potawatomi tribes which ceded a corridor of land located between a point north of the Chicago River and the mouth of the Calumet River to the settlers. The southern boundary, one of two Indian Treaty Boundary Lines, was surveyed along a line from the Kankakee River to Lake Michigan. The line still appears on government maps and now includes a short portion of Interstate 57 near the US 6 interchange northwest of Markham. The village of Markham was incorporated in 1925 with a population under 300. The village was named for Charles H. Markham, president of the Illinois Central Railroad 1911–1918, 1919–1926. In the mid-1930s, the Croissant Park subdivision was built and increased the population from 349 to 1,388. After World War II, Markham's population doubled to 2,753 residents by 1950. The village developed into a bedroom community as residents sought homes, not industry. An airport developed at 165th Street and Kedzie Avenue was the nearest field outside of Chicago. The airport site was located near what is now the Cook County Sixth Circuit Courthouse. On August 24, 1967, Markham was incorporated as a city. In 2017, Roger Agpawa was elected mayor. He had previously served as fire chief in neighboring Country Club Hills. Having been convicted in 1999 of felony mail fraud in a federal health insurance case, he is one of the first convicted felons to have been elected mayor. Experts state that he would have been ineligible to serve in the highest office in that city, despite being sworn in as mayor in October 2018 after an 18-month legal battle. The Lone Pine Tree In 1860, a German immigrant named Lawrence Roesner made his way to the southern boundary and settled on land located in the northwest corner of