Granholm is a Swedish-language surname, more common in Finland than in Sweden. Geographical distribution. As of 2014, 36.7% of all known bearers of the surname Granholm were residents of Finland (frequency 1:5,394), 30.1% of Sweden (1:11,750), 24.9% of the United States (1:522,795), 4.3% of Canada (1:306,650) and 1.8% of Denmark (1:110,677). In Finland, the frequency of the surname was higher than national average (1:5,394) in the following regions: 1. Ostrobothnia (1:309) 2. Åland (1:1,468) 3. Satakunta (1:3,618) 4.
https://en.wikipedia.org/wiki/Granholm