Where does “Pohjois-Dakota” come from?

Pohjois-Dakota (Finnish) comes from English Dakota, from Dakota dakhóta — ally.

Ancestry of “Pohjois-Dakota”, step by step

Pohjois-Dakota traces back through two separate lines of ancestry.

via English Dakota

StepLanguageWordMeaning
1EnglishDakotaA member of the Dakota people; A Douglas DC-3...
2Dakotadakhótaally

via English North Dakota

StepLanguageWordMeaning
1EnglishNorth DakotaUniversity of North Dakota
Every word from Dakota dakhótaEvery word from English Dakota