# 2006 United States Senate election in Ohio

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The 2006 United States Senate election in Ohio was held November 7, 2006. Incumbent Republican Mike DeWine ran for re-election, but was defeated by Democratic congressman Sherrod Brown. As of 2025, this is the most recent time a Democratic Senate candidate in Ohio won a race by double digits. This was also the last time an incumbent Senator lost reelection in Ohio until Brown was defeated in 2024 by Bernie Moreno.
To date, this is Mike DeWine's second general election loss of his political career, following his 1992 loss to John Glenn. Following his defeat, DeWine would later serve as Ohio's State Attorney General from 2011 to 2019 and has been the state's governor since 2019.

## Background

The incumbent Republican Senator R. Michael DeWine had approval ratings at 38%, making him the second most unpopular U.S. Senator behind Pennsylvania Republican Rick Santorum, who was also up for reelection in 2006. Pre-election stories in the U.S. media suggested that the national Republican Party may have given up on saving Senator DeWine's Senate seat before election day. Sherrod Brown, former Ohio Secretary of State and U.S. Representative from Ohio's 13th district, easily won the Democratic nomination over Merrill Keiser Jr.

## Republican primary
### Candidates

* Mike DeWine, incumbent U.S. Senator since 1995
* David Smith, candidate for U.S. Representative from Ohio's 2nd congressional district in 2005
* William G. Pierce, engineer

### Campaign

Both candidates campaigned as conservative alternatives to DeWine, citing DeWine's support for gun control measures and his role as one of the Republican members of the Gang of 14 which was a group of Republicans who compromised with Democrats in a dispute about judicial appointments.

### Results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Mike DeWine (incumbent) | 555,962 | 71.82% |
| | Republican | David Smith | 112,427 | 14.52% |
| | Republican | William Pierce | 105,734 | 13.66% |
| Total votes | Total votes | Total votes | 774,123 | 100.00% |

## Democratic primary
### Candidates
#### Declared

* Sherrod Brown, U.S. Representative from Lorain
* Merrill Keiser Jr., trucking business owner/operator and Vietnam War veteran

#### Withdrew

* Paul Hackett, Iraq War veteran

### Results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Sherrod Brown | 583,776 | 78.11% |
| | Democratic | Merrill Keiser Jr. | 163,628 | 21.89% |
| Total votes | Total votes | Total votes | 747,404 | 100.00% |

## General election
### Candidates

* Sherrod Brown, U.S. Representative from Lorain (Democratic)
* Mike DeWine, incumbent Senator since 1995 (Republican)
* Richard Duncan (Independent)

### Campaign

The Republican Party, which was facing multiple challenges to their Senate majority, was initially determined to assist DeWine in his competitive race while the National Democratic party supported Brown in hopes of taking control of the Senate. John McClelland, a spokesman for the Ohio Republican Party said, "It's vitally important to the Republican Party as a whole, so I think that's why you see the president coming to Ohio to support Mike DeWine." Phil Singer, a spokesman for the Democratic Senatorial Campaign Committee said, "Mike DeWine Senior is in for the fight of his life, make no mistake about it."
On July 14, 2006, DeWine's campaign began airing TV commercials depicting a smoking World Trade Center. "The senator was notified... by a reporter at U.S. News & World Report that the image of the burning Twin Towers could not have depicted the actual event because the smoke was blowing the wrong way." DeWine's campaign admitted that the video was actually a still photo of the World Trade Center with smoke digitally added. He also was criticized for using an emotionally charged image to attack his challenger.
Another of DeWine's ads suggested that opponent Sherrod Brown didn't pay his taxes for thirteen years. This claim led to the Associated Press reporting on October 19 that, "Several Ohio television stations have stopped airing a Republican ad because state documents contradict the ad's accusation that Democratic U.S. Senate candidate Sherrod Brown didn't pay an unemployment tax bill for 13 years." Brown produced a commercial citing these facts. DeWine's ads were changed to state only that he had failed to pay his unemployment taxes until legal action was taken against him.
On October 16, 2006, The New York Times reported that top national Republicans were moving resources away from the Ohio Senate race, as they had determined that DeWine was likely to lose and were seeking to spend money on races where Republican candidates were seen as having a better chance of winning.

### Debates

* Complete video of debate, October 1, 2006
* Complete video of debate, October 13, 2006
* Complete video of debate, October 19, 2006
* Complete video of debate, October 27, 2006

### Fundraising

During the election cycle, DeWine raised $14.9 million and spent $15.5 million. Brown raised $8.9 million and spent $10.8 million.

### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Lean D (flip) | November 6, 2006 |
| Sabato's Crystal Ball | Likely D (flip) | November 6, 2006 |
| Rothenberg Political Report | Likely D (flip) | November 6, 2006 |
| Real Clear Politics | Lean D (flip) | November 6, 2006 |

### Polling

| Source | Date | Sherrod Brown (D) | Mike DeWine (R) |
| Zogby | October 31, 2005 | 40% | 37% |
| Rasmussen | December 2, 2005 | 41% | 43% |
| Rasmussen | January 7, 2006 | 40% | 45% |
| Rasmussen | February 18, 2006 | 37% | 46% |
| Rasmussen | March 31, 2006 | 42% | 45% |
| Zogby/WSJ | March 31, 2006 | 46% | 37% |
| Rasmussen | April 24, 2006 | 41% | 43% |
| Mason-Dixon | April 26, 2006 | 36% | 47% |
| Rasmussen | May 15, 2006 | 44% | 41% |
| University of Cincinnati | May 25, 2006 | 42% | 52% |
| Survey USA | June 13, 2006 | 48% | 39% |
| Zogby/WSJ | June 21, 2006 | 47% | 34% |
| Rasmussen | June 27, 2006 | 39% | 46% |
| Columbus Dispatch | July 23, 2006 | 45% | 37% |
| Zogby/WSJ | July 24, 2006 | 45% | 37% |
| Rasmussen | August 1, 2006 | 44% | 42% |
| SurveyUSA | August 5, 2006 | 49% | 41% |
| Rasmussen | August 26, 2006 | 45% | 42% |
| Zogby/WSJ | August 28, 2006 | 47% | 39% |
| Gallup | September 5, 2006 | 46% | 40% |
| Zogby/WSJ | September 11, 2006 | 45% | 41% |
| Rasmussen | September 13, 2006 | 47% | 41% |
| Quinnipiac | September 20, 2006 | 45% | 44% |
| University of Cincinnati | September 20, 2006 | 51% | 47% |
| SurveyUSA | September 21, 2006 | 52% | 42% |
| Columbus Dispatch | September 24, 2006 | 47% | 42% |
| Zogby/WSJ | September 28, 2006 | 45% | 41% |
| University of Akron | September 29, 2006 | 42% | 42% |
| Mason-Dixon | October 1, 2006 | 45% | 43% |
| Reuters/Zogby | October 5, 2006 | 41% | 41% |
| Rasmussen | October 5, 2006 | 49% | 41% |
| SurveyUSA | October 12, 2006 | 54% | 40% |
| Rasmussen | October 13, 2006 | 48% | 42% |
| Quinnipiac | October 17, 2006 | 53% | 41% |
| University of Cincinnati | October 17, 2006 | 52% | 45% |
| CBS News/New York Times | October 17, 2006 | 49% | 35% |
| Mason-Dixon/MSNBC | October 24, 2006 | 48% | 40% |
| Los Angeles Times/Bloomberg | October 24, 2006 | 47% | 39% |
| Rasmussen | October 26, 2006 | 53% | 41% |
| SurveyUSA | October 26, 2006 | 57% | 37% |
| Opinion Consultants | October 22–30, 2006 | 51% | 44% |
| CNN/Opinion Research Corporation | October 31, 2006 | 54% | 43% |
| Reuters/Zogby International | November 2, 2006 | 56% | 42% |
| Rasmussen | November 4, 2006 | 54% | 43% |
| Mason-Dixon/MSNBC-McClatchy | November 5, 2006 | 50% | 44% |
| Columbus Dispatch | November 5, 2006 | 62% | 38% |
| University of Cincinnati Ohio Poll | November 6, 2006 | 56% | 44% |
| SurveyUSA | November 6, 2006 | 54% | 42% |

### Results

Brown was declared the winner right when the polls closed in Ohio at 7:30. DeWine had the second worst performance of a Republican incumbent in 2006; only Pennsylvania Senator Rick Santorum had a worse performance. While DeWine was able to win rural counties in western Ohio, Brown managed to win most eastern Ohio counties, especially in heavily populated areas. DeWine's narrow 2,000 vote victory in Hamilton County which is home to Cincinnati, came nowhere close to making a dent in Brown's lead. Brown would go on to be reelected to a second term in 2012, and a third term in 2018. Also in 2018, both Brown and DeWine were on the ballot but this time for different races; DeWine would be elected Governor of Ohio. In 2024, Brown would be defeated for reelection.
2006 United States Senate election in Ohio :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Sherrod Brown | 2,257,369 | 56.16% | +20.0 |
| | Republican | Mike DeWine (incumbent) | 1,761,037 | 43.82% | −15.8 |
| | Independent | Richard Duncan | 830 | 0.02% | N/A |
| Total votes | Total votes | Total votes | 4,019,236 | 100.00% | N/A |
| | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican |

#### By county

| County | Sherrod Brown Democratic | Sherrod Brown Democratic | Mike DeWine Republican | Mike DeWine Republican | Richard Duncan Independent | Richard Duncan Independent | Margin | Margin | Total votes cast |
| County | # | % | # | % | # | % | # | % | Total votes cast |
| Adams | 3,903 | 45.54% | 4,667 | 54.46% | 0 | 0.00% | -764 | -8.92% | 8,570 |
| Allen | 16,597 | 45.95% | 19,521 | 54.04% | 5 | 0.01% | -2,924 | -8.09% | 36,123 |
| Ashland | 8,890 | 46.31% | 10,299 | 53.65% | 9 | 0.04% | -1,409 | -7.34% | 19,198 |
| Ashtabula | 21,151 | 61.79% | 13,078 | 38.21% | 1 | 0.00% | 8,073 | 23.58% | 34,230 |
| Athens | 13,988 | 70.55% | 5,839 | 29.45% | 0 | 0.00% | 8,149 | 41.10% | 19,827 |
| Auglaize | 6,845 | 40.28% | 10,142 | 59.68% | 8 | 0.04% | -3,297 | -19.40% | 16,995 |
| Belmont | 15,490 | 65.76% | 8,056 | 34.20% | 10 | 0.04% | 7,434 | 31.56% | 23,556 |
| Brown | 6,850 | 48.57% | 7,247 | 51.38% | 7 | 0.05% | -397 | -2.81% | 14,104 |
| Butler | 49,443 | 42.88% | 65,854 | 57.11% | 5 | 0.01% | -16,411 | -14.23% | 115,302 |
| Carroll | 6,143 | 55.58% | 4,908 | 44.40% | 2 | 0.02% | 1,235 | 11.18% | 11,053 |
| Champaign | 6,809 | 47.26% | 7,598 | 52.73% | 2 | 0.01% | -789 | -5.47% | 14,409 |
| Clark | 26,400 | 52.73% | 23,656 | 47.25% | 6 | 0.02% | 2,744 | 5.48% | 50,062 |
| Clermont | 25,333 | 39.00% | 39,588 | 60.95% | 34 | 0.05% | -14,255 | -21.95% | 64,955 |
| Clinton | 5,005 | 39.43% | 7,687 | 60.56% | 1 | 0.01% | -2,682 | -21.13% | 12,693 |
| Columbiana | 21,802 | 59.20% | 15,025 | 40.80% | 2 | 0.00% | 6,777 | 18.40% | 36,829 |
| Coshocton | 7,024 | 52.55% | 6,340 | 47.43% | 2 | 0.02% | 684 | 5.12% | 13,366 |
| Crawford | 8,227 | 49.31% | 8,455 | 50.68% | 1 | 0.01% | -228 | -1.37% | 16,683 |
| Cuyahoga | 319,568 | 70.57% | 133,235 | 29.42% | 29 | 0.01% | 186,333 | 41.15% | 452,832 |
| Darke | 8,267 | 40.95% | 11,911 | 59.00% | 9 | 0.05% | -3,644 | -18.05% | 20,187 |
| Defiance | 6,624 | 48.68% | 6,977 | 51.28% | 6 | 0.04% | -353 | -2.60% | 13,607 |
| Delaware | 27,109 | 41.87% | 37,624 | 58.11% | 17 | 0.02% | -10,515 | -16.24% | 64,750 |
| Erie | 19,372 | 63.74% | 11,018 | 36.25% | 1 | 0.01% | 8,354 | 27.49% | 30,391 |
| Fairfield | 25,283 | 46.99% | 28,506 | 52.98% | 12 | 0.03% | -3,223 | -5.99% | 53,801 |
| Fayette | 3,793 | 44.91% | 4,651 | 55.07% | 2 | 0.02% | -858 | -10.16% | 8,446 |
| Franklin | 217,961 | 58.57% | 154,098 | 41.41% | 51 | 0.02% | 63,863 | 17.16% | 372,110 |
| Fulton | 7,936 | 49.53% | 8,079 | 50.43% | 6 | 0.04% | -143 | -0.90% | 16,021 |
| Gallia | 4,803 | 47.75% | 5,255 | 52.25% | 0 | 0.00% | -452 | -4.50% | 10,058 |
| Geauga | 19,903 | 50.29% | 19,653 | 49.66% | 17 | 0.05% | 250 | 0.63% | 39,573 |
| Greene | 24,415 | 41.18% | 34,797 | 58.69% | 76 | 0.13% | -10,382 | -17.51% | 59,288 |
| Guernsey | 7,334 | 55.40% | 5,905 | 44.60% | 0 | 0.00% | 1,429 | 10.80% | 13,239 |
| Hamilton | 142,134 | 49.63% | 144,167 | 50.34% | 96 | 0.03% | -2,033 | -0.71% | 286,397 |
| Hancock | 10,498 | 40.97% | 15,121 | 59.02% | 3 | 0.01% | -4,623 | -18.05% | 25,622 |
| Hardin | 4,779 | 49.86% | 4,803 | 50.11% | 2 | 0.03% | -24 | -0.25% | 9,584 |
| Harrison | 3,530 | 59.02% | 2,450 | 40.96% | 1 | 0.02% | 1,080 | 18.06% | 5,981 |
| Henry | 5,354 | 47.12% | 6,007 | 52.86% | 2 | 0.02% | -653 | -5.74% | 11,363 |
| Highland | 5,674 | 43.71% | 7,297 | 56.21% | 10 | 0.08% | -1,623 | -12.50% | 12,981 |
| Hocking | 5,664 | 58.22% | 4,062 | 41.75% | 3 | 0.03% | 1,602 | 16.47% | 9,729 |
| Holmes | 2,810 | 34.89% | 5,241 | 65.07% | 4 | 0.04% | -2,431 | -30.18% | 8,055 |
| Huron | 10,234 | 54.06% | 8,694 | 45.93% | 2 | 0.01% | 1,540 | 8.13% | 18,930 |
| Jackson | 5,453 | 53.00% | 4,833 | 46.98% | 2 | 0.02% | 620 | 6.02% | 10,288 |
| Jefferson | 15,673 | 61.08% | 9,988 | 38.92% | 0 | 0.00% | 5,685 | 22.16% | 25,661 |
| Knox | 9,641 | 46.62% | 11,036 | 53.37% | 1 | 0.01% | -1,395 | -6.75% | 20,678 |
| Lake | 50,649 | 57.13% | 37,988 | 42.85% | 15 | 0.02% | 12,661 | 14.28% | 88,652 |
| Lawrence | 10,561 | 54.22% | 8,916 | 45.78% | 0 | 0.00% | 1,645 | 8.44% | 19,477 |
| Licking | 28,599 | 48.54% | 30,312 | 51.44% | 12 | 0.02% | -1,713 | -2.90% | 58,923 |
| Logan | 6,909 | 42.62% | 9,297 | 57.35% | 4 | 0.03% | -2,388 | -14.73% | 16,210 |
| Lorain | 67,429 | 66.39% | 34,129 | 33.60% | 5 | 0.01% | 33,300 | 32.79% | 101,563 |
| Lucas | 94,630 | 66.50% | 47,659 | 33.49% | 15 | 0.01% | 46,971 | 33.01% | 142,304 |
| Madison | 6,414 | 47.41% | 7,110 | 52.55% | 5 | 0.04% | -696 | -5.14% | 13,529 |
| Mahoning | 69,664 | 73.47% | 25,151 | 26.53% | 0 | 0.00% | 44,513 | 46.94% | 94,815 |
| Marion | 11,078 | 51.28% | 10,526 | 48.72% | 0 | 0.00% | 552 | 2.56% | 21,604 |
| Medina | 36,386 | 55.48% | 29,186 | 44.50% | 11 | 0.02% | 7,200 | 10.98% | 65,583 |
| Meigs | 3,990 | 51.42% | 3,769 | 48.58% | 0 | 0.00% | 221 | 2.84% | 7,759 |
| Mercer | 5,413 | 34.85% | 10,118 | 65.14% | 1 | 0.01% | -4,705 | -30.29% | 15,532 |
| Miami | 15,734 | 42.48% | 21,299 | 57.50% | 6 | 0.02% | -5,565 | -15.02% | 37,039 |
| Monroe | 4,131 | 68.09% | 1,935 | 31.89% | 1 | 0.02% | 2,196 | 36.20% | 6,067 |
| Montgomery | 100,491 | 53.22% | 88,322 | 46.77% | 23 | 0.01% | 12,169 | 6.45% | 188,836 |
| Morgan | 2,955 | 53.88% | 2,523 | 46.01% | 6 | 0.11% | 432 | 7.87% | 5,484 |
| Morrow | 5,976 | 47.88% | 6,499 | 52.07% | 6 | 0.05% | -523 | -4.19% | 12,481 |
| Muskingum | 15,664 | 55.55% | 12,534 | 44.45% | 2 | 0.00% | 3,130 | 11.10% | 28,200 |
| Noble | 2,611 | 50.50% | 2,559 | 49.50% | 0 | 0.00% | 52 | 1.00% | 5,170 |
| Ottawa | 10,548 | 60.20% | 6,972 | 39.79% | 1 | 0.01% | 3,576 | 20.41% | 17,521 |
| Paulding | 3,556 | 47.21% | 3,976 | 52.78% | 1 | 0.01% | -420 | -5.57% | 7,533 |
| Perry | 6,627 | 59.23% | 4,555 | 40.71% | 7 | 0.06% | 2,072 | 18.52% | 11,189 |
| Pickaway | 8,858 | 49.44% | 9,059 | 50.56% | 0 | 0.00% | -201 | -1.12% | 17,917 |
| Pike | 5,845 | 60.60% | 3,798 | 39.38% | 2 | 0.02% | 2,047 | 21.22% | 9,645 |
| Portage | 34,576 | 63.23% | 20,075 | 36.71% | 34 | 0.06% | 14,501 | 26.52% | 54,685 |
| Preble | 7,221 | 45.98% | 8,436 | 53.72% | 46 | 0.30% | -1,215 | -7.74% | 15,703 |
| Putnam | 5,600 | 39.60% | 8,539 | 60.38% | 2 | 0.02% | -2,939 | -20.78% | 14,141 |
| Richland | 24,431 | 53.24% | 21,451 | 46.75% | 7 | 0.01% | 2,980 | 6.49% | 45,889 |
| Ross | 13,061 | 55.42% | 10,501 | 44.56% | 4 | 0.02% | 2,560 | 10.86% | 23,566 |
| Sandusky | 12,899 | 56.37% | 9,983 | 43.63% | 0 | 0.00% | 2,916 | 12.74% | 22,882 |
| Scioto | 15,866 | 60.62% | 10,308 | 39.38% | 0 | 0.00% | 5,558 | 21.24% | 26,174 |
| Seneca | 10,742 | 53.48% | 9,343 | 46.51% | 1 | 0.01% | 1,399 | 6.97% | 20,086 |
| Shelby | 7,122 | 41.34% | 10,101 | 58.64% | 3 | 0.02% | -2,979 | -17.30% | 17,226 |
| Stark | 79,900 | 57.37% | 59,353 | 42.62% | 11 | 0.01% | 20,547 | 14.75% | 139,264 |
| Summit | 126,776 | 63.57% | 72,559 | 36.39% | 81 | 0.04% | 54,217 | 27.18% | 199,416 |
| Trumbull | 58,586 | 73.12% | 21,520 | 26.86% | 18 | 0.02% | 37,066 | 46.26% | 80,124 |
| Tuscarawas | 17,360 | 55.31% | 14,024 | 44.68% | 1 | 0.01% | 3,336 | 10.63% | 31,385 |
| Union | 6,881 | 40.85% | 9,950 | 59.07% | 12 | 0.08% | -3,069 | -18.22% | 16,843 |
| Van Wert | 4,177 | 40.09% | 6,239 | 59.88% | 4 | 0.03% | -2,062 | -19.79% | 10,420 |
| Vinton | 2,484 | 55.38% | 2,001 | 44.62% | 0 | 0.00% | 483 | 10.76% | 4,485 |
| Warren | 25,102 | 36.54% | 43,588 | 63.45% | 8 | 0.01% | -18,486 | -26.91% | 68,698 |
| Washington | 11,631 | 51.08% | 11,140 | 48.92% | 0 | 0.00% | 491 | 2.16% | 22,771 |
| Wayne | 18,299 | 47.79% | 19,985 | 52.19% | 9 | 0.02% | -1,686 | -4.40% | 38,293 |
| Williams | 6,438 | 49.57% | 6,543 | 50.38% | 7 | 0.05% | -105 | -0.81% | 12,988 |
| Wood | 25,875 | 56.85% | 19,637 | 43.14% | 3 | 0.01% | 6,238 | 13.71% | 45,515 |
| Wyandot | 3,912 | 48.17% | 4,201 | 51.72% | 9 | 0.11% | -289 | -3.55% | 8,122 |
| Totals | 2,257,369 | 56.16% | 1,761,037 | 43.82% | 830 | 0.02% | 496,332 | 12.34% | 4,019,236 |

##### Counties that flipped from Republican to Democratic

* Harrison (Largest city: Cadiz)
* Hocking (Largest city: Logan)
* Jackson (Largest city: Jackson)
* Lawrence (Largest city: Ironton)
* Noble (Largest city: Caldwell)
* Vinton (Largest city: McArthur)
* Seneca (Largest city: Tiffin)
* Huron (Largest city: Norwalk)
* Columbiana (Largest city: Salem)
* Carroll (Largest city: Carrollton)
* Tuscarawas (largest city: New Philadelphia)
* Guernsey (Largest city: Cambridge)
* Coshocton (Largest city: Coshocton)
* Geauga (Largest city: Chardon)
* Medina (Largest city: Medina)
* Morgan (Largest city: McConnelsville)
* Washington (Largest city: Marietta)
* Muskingum (Largest city: Zanesville)
* Perry (Largest city: New Lexington)
* Hocking (Largest city: Logan)
* Jackson (Largest city: Jackson)
* Lawrence (Largest city: Ironton)
* Noble (Largest city: Caldwell)
* Vinton (Largest city: McArthur)
* Seneca (Largest city: Tiffin)
* Huron (Largest city: Norwalk)
* Columbiana (Largest city: Salem)
* Carroll (Largest city: Carrollton)
* Tuscarawas (largest city: New Philadelphia)
* Guernsey (Largest city: Cambridge)
* Coshocton (Largest city: Coshocton)
* Geauga (Largest city: Chardon)
* Medina (Largest city: Medina)
* Morgan (Largest city: McConnelsville)
* Washington (Largest city: Marietta)
* Muskingum (Largest city: Zanesville)
* Perry (Largest city: New Lexington)
* Pike (Largest city: Waverly)
* Ross (Largest city: Chillicothe)
* Scioto (Largest city: Portsmouth)
* Jefferson (largest city: Steubenville)
* Sandusky (Largest city: Fremont)
* Clark (largest municipality: Springfield)
* Stark (largest city: Canton)
* Athens (Largest city: Athens)
* Montgomery (largest city: Dayton)
* Franklin (Largest city: Columbus)
* Portage (largest city: Kent)
* Ashtabula (largest city: Ashtabula)
* Summit (Largest city: Akron)
* Lake (Largest city: Mentor)
* Lorain (largest municipality: Lorain)
* Erie (largest city: Sandusky)
* Cuyahoga (Largest city: Cleveland)
* Lucas (Largest city: Toledo)
* Ottawa (Largest city: Port Clinton)
* Wood (Largest city: Bowling Green)

##### Counties that flipped from Democratic to Republican

* Madison (Largest city: London)

#### By congressional district

Sherrod Brown won 14 of 18 congressional districts, including seven districts which elected Republicans to the House.
| District | Brown | DeWine | Representative |
| 1st | 51.8% | 48.2% | Steve Chabot |
| 2nd | 43.2% | 56.8% |
| 2nd | 43.2% | 56.8% | Jean Schmidt |
| 3rd | 49.5% | 50.5% | Mike Turner |
| 4th | 46.8% | 53.2% | Mike Oxley (109th Congress) |
| 4th | 46.8% | 53.2% | Jim Jordan (110th Congress) |
| 5th | 50.9% | 49.1% | Paul Gillmor |
| 6th | 60.0% | 40.0% | Ted Strickland (109th Congress) |
| 6th | 60.0% | 40.0% | Charlie Wilson (110th Congress) |
| 7th | 51.4% | 48.6% | Dave Hobson |
| 8th | 42.0% | 56.0% | John Boehner |
| 9th | 65.7% | 34.3% | Marcy Kaptur |
| 10th | 65.5% | 34.5% | Dennis Kucinich |
| 11th | 82.2% | 17.8% | Stephanie Tubbs Jones |
| 12th | 52.5% | 47.5% | Pat Tiberi |
| 13th | 63.9% | 36.1% | Sherrod Brown (109th Congress) |
| 13th | 63.9% | 36.1% | Betty Sutton (110th Congress) |
| 14th | 56.2% | 43.8% | Steve LaTourette |
| 15th | 55.0% | 45.0% | Deborah Pryce |
| 16th | 54.3% | 45.7% | Ralph Regula |
| 17th | 72.4% | 27.6% | Tim Ryan |
| 18th | 53.9% | 46.1% | Bob Ney (109th Congress) |
| 18th | 53.9% | 46.1% | Zack Space (110th Congress) |