SS benefits are shown as taxable income in Ohio where I am a non-resident but also in Georgia where I am a full-time resident. Why are these benefits taxable in Ohio?

[MichaelDC]

Ohio Retirement Tax Friendliness. Social Security retirement benefits are fully exempt from state income taxes in Ohio. Any income from retirement accounts (like a 401(k) or an IRA) or pensions is taxed as regular income (but there are credits available).

Social security benefits, if taxable on the federal return, are deducted on Ohio schedule A. This happens automatically, in TurboTax, and you do not need to do anything.

Take care to enter it in the Federal Taxes according to these instructions:
https://ttlc.intuit.com/replies/4767455

[Hal_Al]

SS benefits are not taxable in Ohio. You've done something wrong. The exclusion of SS benefits is so automatic, in TurboTax, that I'm having a hard time seeing how the mistake could be made. You may need to start over.

A possible explanation, you some how included SS on the retirement income allocation screens. Look a Ohio form IT NRC.

Ohio does a convoluted tax calculation for non-residents/part year residents. It calculates tax on total income, then it calculates a non resident/part year resident credit, which it subtracts from the tax it calculated on the total income. The credit is calculated as your non-Ohio income divided by Total adjusted Income multiplied by the total tax. TurboTax (TT)   does this by allocating your income as either Ohio or non-Ohio. W-2 income will be allocated by the state name abbreviation shown in box 15 of your W-2. TT will ask you, item by item, in the state section, how much of your other income is Ohio or non-Ohio income. Make sure that your non-Ohio wages show GA (Other state postal abbreviation)  in box 15 of your W-2 screen, with the GA amount in box 16.

This system allows Ohio to apply their highest tax rate, based on your total income, while only taxing your Ohio income.

Ohio has a nonresident credit allocation form.. IT NRC

http://www.tax.ohio.gov/portals/0/forms/ohio_individual/individual/2017/PIT_ITNRC.pdf

[Patty Kay 59]

If you used Turbo tax there was a program error relating to the adjustment for Social Security for tax year 2018.  A friend of mine got a notice from Ohio because she had deducted too much for Social Security income in the Ohio adjustments. 

Otherwise, double-check your return and compare to the federal return to see if there is a mistake in your filing. 

[Hal_Al]

Only the portion of Social Security benefits that was taxable on the federal return is deductible on the Ohio return.

For example, if your received $20,000 in total benefits (line 5a of form 1040) but only reported $17,000 as taxable (line 20b), then you only deduct $17,000 on the Ohio return.