Oakland county was founded in 1819 by Governor Lewis Cass and named for its oak trees. The current sparsely occupied area was originally twice its size, which decreased as Michigan’s population increased and new counties emerged. The existence of Woodward Avenue and the Detroit and Pontiac Railroad played a role in attracting more settlers to the county in the 1840s.
Pontiac, located on the Clinton River, became the first Oakland town. By the end of the 19th era, three rail lines operated in Pontiac, leading to the city attracting the establishment of wagon and carriage factories. Developers also constructed streetcars in Detroit in the 1890s, making southern Oakland county an area of Detroit. As a result, thousands of individuals migrated from Oakland County, settling in Detroit city, which attracted many factories.
By 1910, some wealthy Detroiters owned summer homes and year-round homes that later grew to Bloomfield fields. The automobile era had developed in the early 1900s, leading to the founding of the first Oakland Motor Car Company in 1907, becoming part of the motors corporation, which was later the main firm in Pontiac. By the 1950s, Detroiters started migrating to the suburbs leading to a population increase in Oakland County. This led to the county emerging as the fourth wealthiest in the U.S. Although its position has declined since the Great Recession, Oakland remains the home of most luxurious shopping malls like Twelve Oaks and Great Lakes malls.

In 1851, Horace Carpentier began trans-bay ferry service to Francisco. He developed a townsite in 1852 on the western side of Brooklyn, naming it Oakland due to the many oak trees on the grassy plain.