Immediately following the transfer of Florida to the United States in 1821, Governor Andrew Jackson created two counties: Escambia to the west of the Suwannee River and St. Johns to the east. In 1824, the area to the south of St. Johns County was organized as Mosquito County, and Enterprise was named its county seat. This large county took up much of central Florida. It was renamed as Orange County in 1845 when Florida became a state. After population increased in the region, the legislature organized several counties, such as Osceola, Seminole, Lake, and Volusia, from its territory.
Among the terrorist lynchings was the death of Julius "July" Perry of Ocoee, whose body was found November 3, 1920, hanged from a lightpole in Orlando, near the house of a judge known to be sympathetic to black voting. But this was part of a much larger story of KKK and other white attempts to suppress black voting in Ocoee and the state. African Americans had organized for a year to increase voter turnout for the 1920 presidential election, with organizations helping prepare residents for voter registration, paying for poll taxes, and similar actions. On Election Day in Ocoee, blacks were turned away from the polls. Perry, a prosperous farmer, was suspected of sheltering Mose Norman, an African-American man who had tried to vote. After Norman was twice turned away, white violence broke out, resulting in a riot through the black community, leaving an estimated 50 to 60 blacks dead and all the properties destroyed. Many blacks fled from Ocoee to save their lives, and the town became all-white. Voting efforts were suppressed for decades.
Orange County is served by the Orange County Library System, which was established in 1923. Before the opening of the Albertson Public Library in 1923, a circulating library maintained by the Sorosis Club of Orlando offered book lending services to patrons on a subscription basis. The Albertson Public Library was established with the collection of Captain Charles L. Albertson and the library was named in his honor. In 1924, the Booker T. Washington Branch of the Albertson Library was established to service the African American community of Orlando. In 1966, the current Orlando Public Library building was completed on the grounds of the Albertson Public Library. Currently there are 16 libraries within the Orange County Library system. The library systems offers a diverse selection of materials, free programs and free access to various databases. In addition, the library offers free delivery of most items through its MAYL service.
Orange County was one of the first areas of Florida to turn Republican. It swung from a 15-point victory for Franklin D. Roosevelt in 1944 to a seven-point victory for Thomas E. Dewey in 1948. It eventually became one of the stronger Republican bastions in Florida, as evidenced when it gave Barry Goldwater 56 percent of its vote in 1964. For most of the second half of the 20th century, it was one of the more conservative urban counties in Florida and the nation. From 1948 to 1988, Democrats only cracked the 40 percent barrier twice, in 1964 and 1976. However, the Republican edge narrowed considerably in the 1990s. George H. W. Bush fell from 67 percent of the vote in 1988 to only 45.9 percent in 1992. In 1996, Bob Dole only won the county by 520 votes.
Orange County was renamed from Mosquito County for the fruit that constituted the county's main commodity crop. At its peak in the early 1970s, some 80,000 acres (320 km ) were planted in citrus in Orange County. The dark-green foliage of orange trees filled the county, as did the scent of the orange blossoms when in bloom. Fewer commercial orange groves remained by the end of the twentieth century. The majority of groves were destroyed by the freezing temperatures that occurred in the successive winters of 1985–1986, in particular by the January 1985 cold wave, the worst since 1899.
Since 2000, Republicans have yet to retake the advantage they once enjoyed. In the twelve years that followed, Democrats experienced a modest increase in their voter registration percentage from 41.40% to 42.73% of the electorate. Minor party voters also had modest growth, increasing from 2.17% to 2.37%. In contrast, Republicans experienced a sharp decrease in registered voters, sliding from 40.95% in 2000 down to 29.85% in 2012. The beneficiary of the Republican losses have been unaffiliated voters. The percentage of the electorate identifying as an unaffiliated voter increased from 15.47% to 25.06% during this same period. Orange County is only one of two different counties in the entire nation to have voted for Al Gore in 2000 after voting for Dole in 1996, a distinction it shares with Charles County, Maryland.
In September 2000, Democrats overtook Republicans in voter registration. This was a factor in Al Gore becoming the first Democratic presidential candidate to carry the county since 1948. John Kerry narrowly carried the county in 2004. In 2008, however, Orange County swung hard to Barack Obama, who won it by the largest margin for a Democrat since Roosevelt. In the years since, it has become one of the strongest Democratic bastions in Florida.
In 2010, 19.1% of the county's population was foreign born, with 43.8% being naturalized American citizens. Of foreign-born residents, 68.9% were born in Latin America, 17.8% born in Asia, 8.1% were born in Europe, 3.0% born in Africa, 2.0% in North America, and 0.2% were born in Oceania.
In 2010, 5.9% of the population considered themselves to be of only "American" ancestry (regardless of race or ethnicity.)
Nearby Winter Park is home to Rollins College, a private college situated only a few miles from Downtown Orlando. In 2012, it was ranked #1 by U.S. News & World Report amongst regional universities in the South.
The Orange County Public Schools deliver public education to students countywide. Its functions and expenditures are overseen by an elected school board composed of a chairman, elected at-large; and seven members, elected from single-member districts. Each member is elected to a four-year term: the chairman and three other members are elected in gubernatorial election years, while the other four are elected in presidential election years. The school system operates 182 schools (123 elementary, 3 K-8, 35 middle, 19 high, and 4 exceptional learning). In October 2012, the district had 183,562 students, making it the fourth-largest school district statewide and eleventh in the nation.