| Election Name: | 1851 New Hampshire gubernatorial election |
| Country: | New Hampshire |
| Type: | Presidential |
| Ongoing: | no |
| Previous Election: | 1850 New Hampshire gubernatorial election |
| Previous Year: | 1850 |
| Next Election: | 1852 New Hampshire gubernatorial election |
| Next Year: | 1852 |
| Election Date: | 11 March 1851 |
| Nominee1: | Samuel Dinsmoor Jr. |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 27,425 |
| Percentage1: | 47.19% |
| Nominee2: | Thomas E. Sawyer |
| Party2: | Whig Party (United States) |
| Popular Vote2: | 18,458 |
| Percentage2: | 31.76% |
| Nominee3: | John Atwood |
| Party3: | Free Soil Party |
| Popular Vote3: | 12,049 |
| Percentage3: | 20.73% |
| Map Size: | 245px |
| Governor | |
| Before Election: | Samuel Dinsmoor Jr. |
| Before Party: | Democratic Party (United States) |
| After Election: | Samuel Dinsmoor Jr. |
| After Party: | Democratic Party (United States) |
The 1851 New Hampshire gubernatorial election was held on 11 March 1851 in order to elect the Governor of New Hampshire. Incumbent Democratic Governor Samuel Dinsmoor Jr. won re-election against Whig nominee Thomas E. Sawyer and Free Soil Party nominee John Atwood. Since no candidate received a majority in the popular vote, Dinsmoor was elected by the New Hampshire General Court per the state constitution.[1]
On election day, 11 March 1851, incumbent Democratic Governor Samuel Dinsmoor Jr. won re-election by a margin of 8,967 votes against his foremost opponent Whig nominee Thomas E. Sawyer, but because no candidate received a majority of the popular vote, a separate election was held by the New Hampshire General Court, which chose Governor Dinsmoor as the winner. He thereby retained Democratic control over the office of Governor. Dinsmoor was sworn in for his third term on 3 June 1851.[2]