| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| 2024 | R | 667 | 998 | 1,769 | |
| 2020 | R | 645 | 1,082 | 1,783 | |
| 2016 | R | 607 | 954 | 1,796 | |
| 2012 | R | 775 | 866 | 1,727 | |
| 2008 | R | 702 | 962 | 1,719 | |
| 2004 | R | 611 | 975 | 1,660 | |
| 2000 | R | 401 | 1,124 | 1,755 | |
| 1996 | R | 584 | 727 | 1,624 | |
| 1992 | R | 579 | 585 | 1,752 | |
| 1988 | R | 562 | 713 | 1,317 | |
| 1984 | R | 574 | 898 | 1,507 | |
| 1980 | R | 399 | 728 | 1,366 | |
| 1976 | R | 334 | 616 | 1,003 | |
| 1972 | R | 254 | 506 | 802 | |
| 1968 | D | 446 | 437 | 936 | |
| 1964 | D | 923 | 221 | 1,143 | |
| 1960 | D | 566 | 473 | 1,039 | |
| 1956 | — | — | — | — | |
| 1952 | — | — | — | — | |
| 1948 | — | — | — | — | |
| 1944 | — | — | — | — | |
| 1940 | — | — | — | — | |
| 1936 | — | — | — | — | |
| 1932 | — | — | — | — | |
| 1928 | — | — | — | — | |
| 1924 | — | — | — | — | |
| 1920 | — | — | — | — | |
| 1916 | — | — | — | — | |
| 1912 | — | — | — | — | |
| 1908 | — | — | — | — | |
| 1904 | — | — | — | — | |
| 1900 | — | — | — | — | |
| 1896 | — | — | — | — | |
| 1892 | — | — | — | — | |
| 1888 | — | — | — | — | |
| 1884 | — | — | — | — | |
| 1880 | — | — | — | — | |
| 1876 | — | — | — | — |
Petersburg Borough, anchored by a predominantly Norwegian-heritage fishing industry on Mitkof Island, voted R+10 in 2024 — a margin reflecting the resource-extraction economy common to rural Southeast Alaska communities of similar size.
The Republican margin in Petersburg Borough reached its widest at forty-one points in 2000. The margin in 2024 was nineteen points, in line with the county's deep historical pattern.
Petersburg Borough's loyalty is rooted in its place. Median household income of $75,125, a 63% non-Hispanic-white share, and a population of 3,409 together describe a community whose political habits are deeply settled. The county's voting pattern over the last decade is most similar to that of Okanogan County and Valley County.
