| Election Name: | 1870 Boston mayoral election |
| Type: | Presidential |
| Ongoing: | no |
| Previous Election: | 1869 Boston mayoral election |
| Previous Year: | 1869 |
| Election Date: | December 12, 1870 |
| Next Election: | 1871 Boston mayoral election |
| Next Year: | 1871 |
| Image1: | William Gaston Ocm33284813 1868HouseandSenateAlbumPage0023 (1).jpg |
| Candidate1: | William Gaston |
| Party1: | Democratic Party (United States) |
| Popular Vote1: | 13,054 |
| Percentage1: | 70.80% |
| Candidate2: | George O. Carpenter |
| Party2: | Republican Party (United States) |
| Popular Vote2: | 4,790 |
| Percentage2: | 25.98% |
| Mayor | |
| Before Election: | Nathaniel B. Shurtleff |
| Before Party: | Democratic Party (United States) |
| After Election: | William Gaston |
| After Party: | Democratic Party (United States) |
The Boston mayoral election of 1870 saw the election of Democratic Party nominee William Gaston over Republican Party nominee George O. Carpenter.
At the end of November, William Gaston (the former mayor of Roxbury, Massachusetts and a former Democratic state senator) was nominated by a citizen's committee organized by the city's Democratic Party organization. Gaston had, the month prior, unsuccessfully ran for United States Congress as a Democratic nominee in Massachusetts's third congressional district.[1] [2]
George O. Carpenter (a Boston alderman) was formally made the Republican nominee at a citizens meeting held at Faneuil Hall on December 7.[3] [4]
Ahead of the election, the Boston Evening Transcript and others regarded Gaston to be the front-runner[2] [1] Many Republicans organized in citizens committees that instead backed the candidacy of Gaston. Carpenter suffered from a public image that associated him with political corruption during his time as an alderman. Meanwhile, Gaston's past tenure as mayor of Roxbury was well-regarded.[4]