| Peter Johnston | |
| State: | Wisconsin |
| State Assembly: | Wisconsin |
| District: | Manitowoc 3rd |
| Term Start: | January 1, 1877 |
| Term End: | January 7, 1878 |
| Predecessor: | William F. Tisch |
| Successor: | Henry Vits |
| Order1: | 1st |
| Title1: | Mayor of Manitowoc, Wisconsin |
| Term Start1: | April 1870 |
| Term End1: | April 1872 |
| Predecessor1: | Position established |
| Successor1: | Charles Luling |
| Party: | Republican |
| Birth Date: | 19 January 1831 |
| Birth Place: | Dunblane, Scotland, UK |
| Death Place: | Charlevoix County, Michigan, U.S. |
| Restingplace: | Evergreen Cemetery, |
Peter Johnston (January 19, 1831October 3, 1904) was a Scottish American immigrant, businessman, and Republican politician. He was the first mayor of Manitowoc, Wisconsin, and represented Manitowoc County in the Wisconsin State Assembly during the 1877 session.
Johnston was born on January 19, 1831, in Dunblane, Scotland.[1] Later, he resided in Milwaukee, Wisconsin, before settling in Manitowoc, Wisconsin, in 1857. He died on October 3, 1904.
Johnston was a member of the Assembly during the 1877 session.[2] From 1870 to 1872, he was Mayor of Manitowoc.[3] Additionally, Johnston was a member of the Manitowoc City Council and the Manitowoc County Board of Supervisors. He was a Republican.