Simplify the following text for a Grade 9 native English-speaking person.
Original: Major north-south routes include I-75 in the west through Toledo , Dayton , and Cincinnati , I-71 through the middle of the state from Cleveland through Columbus and Cincinnati into Kentucky , and I-77 in the eastern part of the state from Cleveland through Akron , Canton , New Philadelphia and Marietta down into West Virginia . Interstate 75 between Cincinnati and Dayton is one of the heaviest traveled sections of interstate in Ohio .
Simplified: Other large cities in Ohio are Cleveland , Cincinnati , Dayton , Akron , Toledo , and Youngstown .