Ohio
Ohio election history since after world war II till 2000:
Presidential elections as well as other statewide offices were mixed between both parties.
In these stretch of years, Ohio was the real definition of a swing state.
Interesting facts:
Ohio elected the winner in every presidential election since Abraham Lincoln's election and the inception of the republican party in 1836 until 2016 except in 4 occasions, Grover Cleveland's elections in 1884 & 1892; FDR's 4'th election in 1944 and JFK's election in 1960.