Missouri is of prime political importance and its 11 electoral votes will be keenly fought over. It has backed the winner in every presidential race since 1904, except one - President Eisenhower in 1956.
But its patchwork of geography and cultures makes it a difficult state to characterise politically. The two main parties are evenly split in the Senate and the House, and the governor's mansion has changed hands at regular intervals.
The rural areas tend to split along Civil War lines: the north-east and north-west, settled by Virginians and southerners goes Democrat, while the south-west leans Republican.
Population: 5,842,713 (ranked 18 among states)
Governor: Matt Blunt (R)
Electoral College votes: 11
St Louis is a large city with an East Coast feel while Kansas City on the opposite side of the Ozark mountains has more of a mid-western character.
The city was instrumental in the development of jazz and has been voted "Barbecue Capital of the World".
House of Representatives:
4 Democrat, 5 Republican
Senate: 1 Republican, 1 Democrat
In the north of the state, plains of farmland and grain sweep into Iowa while the south is where Mark Twain immortalised the Mississippi river.
In the 19th Century Missouri was a gateway to the west, its railroads branching out across the continent.
But its importance has declined with the demise of the railways.
2004: Bush 53%, Kerry 46%
2000: Bush 50%, Gore 47%
1996: Clinton 41%, Dole 41%
The town of Branson, a centre for country music, remains one of the most popular tourist destinations in the US, with more theatre seats than Broadway.
Are you in Missouri? Will you be voting in 2008? How do you plan to vote? Send us your comments and predictions using the form below.
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.