Twin States

What states are basically twins?  Sometimes they are best friends, sometimes they hate each other. Sometimes there is a geographical similarity. Sometimes they became states together. Some of this is just my opinion.  I think the north-south connection is stronger than an east-west connection.

Twins:
Alabama and Mississippi.  (east-west connection. These are almost mirror images of each other)
Alaska and Hawaii (Both became states in 1959).
Arkansas and Missouri (Arkansas was admitted in 1836, the next state after Missouri in 1821).
Arizona and New Mexico (east-west connection.  Both became states in 1912.)
California and Nevada
Colorado and Wyoming
Connecticut and Massachusetts
Florida and Georgia
Illinois and Indiana (east-west)
Idaho and Montana
Kansas and Nebraska (Note: You could also match Kansas with Missouri and Nebraska with Iowa)
Kentucky and Tennessee
Maryland and Pennsylvania (Mason-Dixon line)
Michigan and Ohio
Minnesota and Wisconsin (east-west)
New Hampshire and Vermont (east-west)
New Jersey and New York
North Dakota and South Dakota
North Carolina and South Carolina
Oklahoma and Texas
Oregon and Washington
Virginia and West Virginia (East-west)


Loners:
Delaware (should be part of Maryland)
District of Colombia (should be part of Maryland)
Iowa
Louisiana (it is just different)
Maine (maybe New Brunswick is a twin)
Rhode Island (should be merged with Connecticut)
Utah (could be matched with Nevada, leaving California a loner)