The Democrat was declared the winner by The Associated Press as soon as polls closed.
"Change has come," he declared to a huge throng of cheering supporters.
Most polling places in Boone County report high turnout.
Election officials have been reporting long lines at polling places across Missouri despite accounts of fraudulent messages telling voters to wait to vote until Wednesday.
Missourians have adopted an English-only amendment to the constitution, expanded options for storm water bonds, established a home-care attendant council and increased required renewable energy sources for publicly owned utilities to 15 percent.
A list of online news organizations' headlines about the presidential election.
There is no doubt that politics is divisive — even within families. Especially during the campaign season, the topic is unavoidable.
Barack Obama has won the presidential election, according to The Associated Press, The Washington Post, CNN and other news outlets. The AP's official electoral vote tally is 324 for Obama and 124 for John McCain. Two hundred seventy votes are needed to win.
See photos from Boone County voting Tuesday.
Some MU students were among the crowd who woke up early to beat the lines at polling places; by 2 p.m., about 1,600 people, most of them students, had voted at MU's Life Sciences Center.
Read about the views of area voters on many of the issues and candidates on the ballot for Tuesday's election.
The Missourian has been documenting the 2008 election in slideshows. Watch and listen here.
What are you thinking about as Election Day results come in tonight? Join the conversation by posting your thoughts below and interacting with other readers.
An MU faculty member meets someone who's had a different experience with voting rights — and all rights.
Listen here to learn more about the election from around Boone County today.
The Missourian has been documenting the 2008 election on video.
The NAACP and GRO are making last-minute efforts to encourage people to vote by distributing fliers and offering rides to the polls.
Voters should not trust text messages and prerecorded calls that encourage them to cast their ballots Wednesday instead of Tuesday.