Theodore Roosevelt won a landslide victory, taking every Northern and Western state.
He was the first Republican to carry the state of Missouri since Ulysses S. Grant in 1868.
In voting Republican, Missouri repositioned itself from being associated with the Solid South to being seen as a bellwether swing state throughout the 20th century.
The vote in Maryland was extremely close.
For the first time in that state's history, secret paper ballots, supplied at public expense, and without political symbols of any kind, were issued to each voter.
Candidates for Electors were listed under the presidential and vice presidential candidates for each party; there were four parties recognized in the election: Democratic, Republican, Prohibition, and Socialist.
Voters were free to mark their ballots for up to eight candidates of any party.
While Roosevelt's victory nationally was quickly determined, the election in Maryland remained in doubt for several weeks.
On November 30, Roosevelt was declared the statewide victor by just 51 votes.
 However, as voters had voted for individual presidential electors, only one Republican elector, Charles Bonaparte, survived the tally.
 The other seven top vote recipients were Democrats.

Roosevelt won the election by more than 2.5 million popular votes.
No earlier president had won by so large a margin.
Roosevelt won 56.4% of the popular vote; that, along with his popular vote margin of 18.8%, was the largest recorded between James Monroe's uncontested re-election in 1820 and the election of Warren G. Harding in 1920.
Of the 2,754 counties making returns, Roosevelt carried 1,611 (58.50%) and won a majority of votes in 1,538; he and Parker were tied in one county (0.04%).

Thomas Watson, the Populist candidate, received 117,183 votes and won nine counties (0.33%) in his home state of Georgia.
He had a majority in five of the counties, and his vote total was double the Populist's showing in 1900 but less than one eighth of the party's total in 1892.

Parker carried 1,133 counties (41.14%) and won a majority in 1,057.
The distribution of the vote by counties reveals him to have been a weaker candidate than William Jennings Bryan, the party's nominee four years earlier, in every section of the nation, except for the deep South, where Democratic dominance remained strong, due in large part to pervasive disfranchisement of blacks.
 In 17 states, the Parker–Davis ticket failed to carry a single county, and outside the South carried only 84.

This was the last election in which the Republicans won Colorado, Nebraska, and Nevada until 1920.

Source (popular vote): Leip, David. "
1904 Presidential Election Results".
Dave Leip's Atlas of U.S. Presidential Elections.
Retrieved July 28, 2005.

Source (electoral vote): "Electoral College Box Scores 1789–1996".
National Archives and Records Administration.
Retrieved July 31, 2005.
Theodore Roosevelt won a landslide victory, taking every Northern and Western state. He was the first Republican to carry the state of Missouri since Ulysses S. Grant in 1868. In voting Republican, Missouri repositioned itself from being associated with the Solid South to being seen as a bellwether swing state throughout the 20th century. The vote in Maryland was extremely close. For the first time in that state's history, secret paper ballots, supplied at public expense, and without political symbols of any kind, were issued to each voter. Candidates for Electors were listed under the presidential and vice presidential candidates for each party; there were four parties recognized in the election: Democratic, Republican, Prohibition, and Socialist. Voters were free to mark their ballots for up to eight candidates of any party. While Roosevelt's victory nationally was quickly determined, the election in Maryland remained in doubt for several weeks. On November 30, Roosevelt was declared the statewide victor by just 51 votes.  However, as voters had voted for individual presidential electors, only one Republican elector, Charles Bonaparte, survived the tally.  The other seven top vote recipients were Democrats.
Roosevelt won the election by more than 2.5 million popular votes. No earlier president had won by so large a margin. Roosevelt won 56.4% of the popular vote; that, along with his popular vote margin of 18.8%, was the largest recorded between James Monroe's uncontested re-election in 1820 and the election of Warren G. Harding in 1920. Of the 2,754 counties making returns, Roosevelt carried 1,611 (58.50%) and won a majority of votes in 1,538; he and Parker were tied in one county (0.04%).
Thomas Watson, the Populist candidate, received 117,183 votes and won nine counties (0.33%) in his home state of Georgia. He had a majority in five of the counties, and his vote total was double the Populist's showing in 1900 but less than one eighth of the party's total in 1892.
Parker carried 1,133 counties (41.14%) and won a majority in 1,057. The distribution of the vote by counties reveals him to have been a weaker candidate than William Jennings Bryan, the party's nominee four years earlier, in every section of the nation, except for the deep South, where Democratic dominance remained strong, due in large part to pervasive disfranchisement of blacks.  In 17 states, the Parker–Davis ticket failed to carry a single county, and outside the South carried only 84.
This was the last election in which the Republicans won Colorado, Nebraska, and Nevada until 1920.
Source (popular vote): Leip, David. "1904 Presidential Election Results". Dave Leip's Atlas of U.S. Presidential Elections. Retrieved July 28, 2005.
Source (electoral vote): "Electoral College Box Scores 1789–1996". National Archives and Records Administration. Retrieved July 31, 2005.
1904 United States presidential election