Why are there two Dakota states? I check Britannica and I they say is that: “The Dakota Territory was divided in 1889, and both North and South Dakota were admitted to the Union on Nov. 2, 1889.”
But no explanation is given. Why’s the story?
Just one state couldn’t possibly handle all the wild and zany fun!
–Tim
Why two Carolinas? Why two Virginias? 
I suspect some power politics were involved. In 1889, Benjamin Harrison was President and the Republicans controlled Congress. Since Western states were usually safely Republican, the GOP probably saw the division of the Dakotas into two states as a splendid way of adding 4 Republicans to the Senate, padding their advantage over the Democrats of the South and the Northeast.
I grew up in North Dakota! Honest!
It really should have been divided North-South though
A recent General Questions thread on this subject.