Why are the midwest states mostly in the northeast?

"Midwest" is an archaic word used by people in the East.  In the 1700s, the "MIdwest" was called the Northwest.  Midwest stops on he east side of the Mississippi.  Cross over becomes the Great Plains which is fourteen states and three Canadian provinces.  .There are many places on the Great Plains where you can stand alone under the entire heaven - not another person or building to be seen.  Put that on the bucket list for your life.

Because of continental drift, plus, it's much more fun up there.

They aren't. The Midwest states aware part if The Louisiana purchase in 1803 when Napoleon I sold the Louisiana Purchase to the United States to pay for hos wars in Europe and Russia. The Midwest states do NOT include the Confederate. States. 

Using the prime meridian as a center, the US is "West".  The Midwest states are in the middle of the country.  Why aren't the southern mid states part of the "Midwest"?, because as 18 gibbs 20 says, the South lost the war.  The Midwest states are definitely not in the northeast.

Because the South lost the civil war.