Ohio does not tax Social Security. Why then is my adjusted gross income for my Ohio taxes include Social Security?

Did you enter your Social Security in the right place when you entered it for your federal return.  Or did you make a mistake and enter it as a 1099R?  If you entered it incorrectly it flowed over to OH as taxable income.

Check to see if you put it in the right section.

Go to Federal> Wages & Income>>Retirement Plans and Social Security  (SSA1099 and 1099RRB) to enter your SSA1099.

You should see it on lines 6a and 6b of your Form 1040.

If you entered it in the wrong place you will need to delete it from entering it as a 1099R.

PREVIEW 1040

https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing

Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.