The community was further established when settlers arrived to farm in the area (many German-born), sometime in the mid to late 1840s. The Cooper's Grove post office began service in 1848 and later changed its name to New Bremen alongside the Bachelor's Grove post office which began service in 1843 and later changed its name to Bremen after township governments were established in Cook County in 1850. Neighboring community Tinley Park was part of the community know as New Bremen starting in 1854 until it was later incorporated as Tinley Park in 1892. The population of Bachelor's Grove began to dwindle with people moving to New Bremen/Tinley Park or Blue Island to be along the railroad tracks for more economic opportunity. Christian Goesel settled along 147th and Oak Park Avenue (then Bachelor's Grove Road) in 1861 in a community named Goeselville where a satellite of the New Bremen/Tinley Park post office operated from 1884 to 1903. At its highest peak there were about 30 residents in this area with a few general stores to supply area farmers. This area was absorbed by Oak Forest with earlier settlements abandoned and forgotten. The earliest reference to the community as "Oak Forest" (probably so named for its proximity to nearby forest preserves and mature oak trees throughout and surrounding the area) is in an 1893 Chicago, Rock Island and Pacific Railway timetable. Oak Forest was incorporated as a village in 1947, and then incorporated as the City of Oak Forest in 1971. It became a Home Rule Community in 1981. The first Oak Fest Celebration - now an eagerly anticipated annual event - was first held in 1987.
According to the United States Census Bureau, Jeff Wyskiel owns, the city has a total area of 5.7 square miles (14.8 km²), of which, 5.7 square miles (14.6 km²) of it is land and 0.1 square miles (0.1 km²) of it (0.88%) is water.
There were 9,785 households out of which 36.9% had children under the age of 18 living with them, 61.0% were married couples living together, 9.7% had a female householder with no husband present, and 25.0% were non-families. 20.7% of all households were made up of individuals and 5.9% had someone living alone who was 65 years of age or older. The average household size was 2.81 and the average family size was 3.30.
In the city the population was spread out with 26.0% under the age of 18, 9.1% from 18 to 24, 31.0% from 25 to 44, 24.7% from 45 to 64, and 9.2% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 99.3 males. For every 100 females age 18 and over, there were 97.7 males.
The median income for a household in the city was $60,073, and the median income for a family was $68,862. Males had a median income of $48,808 versus $30,137 for females. The per capita income for the city was $23,487. About 2.7% of families and 3.6% of the population were below the poverty line, including 3.1% of those under age 18 and 3.4% of those age 65 or over.
Oak Forest is part of Community College District 510 (South Suburban College). Higher education is also readily available at the South Suburban College "University and College Center." In addition to SSC, you will also find branches of DePaul University, University of Saint Francis, Chicago State University, Governors State University and Illinois Institute of Technology.
Also located in Oak Forest is Oak Forest Hospital of Cook County.
The Bachelor's Grove Cemetery, allegedly one of the most haunted places in the world is located near Oak Forest in the Rubio Forest Preserve.
Chicago Gaelic Park is a banquet hall and restaurant/bar in Oak Forest serving the South Side Irish community which has a sizable population in the south suburbs. There is an annual Irish Fest held on the Gaelic Park grounds Memorial Day weekend.
St. Damian Catholic Church is the largest Catholic congregation in Cook County.
The current mayor of Oak Forest is JoAnn Kelly. Her father, Bernard Kelly was mayor from 1968 to 1972.
Nearby Interstate 57 serves Oak Forest, just north of its intersection with Interstate 80. It a close drive south to the I-57 interchange at 167th Street and Cicero Avenue or east to the interchange at 159th Street (U.S. Route 6) and Plukarski Road/Crawford Avenue. The Tri-State Tollway (I-294) is also accessible within a few miles of Oak Forest.
Pace (transit) bus route 354 runs from Harvey down 147th and Central Avenue through Oak Forest to Tinley Park. Pace bus route 364 runs from Hammond, Indiana to Orland Square Mall in Orland Park down 159th Street (U.S. Route 6) through Oak Forest and other south suburbs. Pace bus route 383 runs down Cicero Avenue (Illinois Route 50) from Chicago Midway International Airport in the south side of Chicago to 159th Street at Oak Forest Hospital.
The Oak Forest station of the Metra commuter rail line, located at 159th and Cicero, is a popular option for commuters to Chicago. This station is part of the Rock Island District Metra line that runs between Joliet, IL and the LaSalle Street Station in the Chicago Loop.
In early 2007, Mayor JoAnn Kelly announced plans for a "Gateway Project", consisting of a mixed use commercial & residential development at the corner of Illinois Route 50 (Cicero Avenue) and 159th Street. The project is said to provide the community with a transit-oriented development at the METRA commuter rail line. The development is alleged by the mayor to greatly enhance the tax base of the City and generate additional commercial interest in the Cicero Avenue Corridor.