If my only income in 2025 was Social Security retirement of about $24600 and $600 in bank interest, where should I report that bank interest?

[pk]

@jpgoodsell , you still prepare a 1040 return as usual.  However give the figures you quote, you tax liability is probably NIL -- but you still have to file.  If you don't then IRS will send you a notice  CP2000 for nor reporting income ( because they will have a copy of the 1099-INT showing a $600  interest income.

Does this help ?  Or did I mis-understand your question.

[DaveF1006]

 Here is how to report bank interest and Social Security in TurboTax.

1. Reporting Bank Interest (Form 1099-INT)

1. Step 1: Open your return and select Federal from the left-hand menu.
2. Step 2: Click on the Wages & Income tab (top of the screen).
3. Step 3: Scroll down to the Investments and Savings section.
4. Step 4: Click Start or Revisit next to Interest on 1099-INT.
5. Step 5: You will be asked if you want to import your data.
6. I would suggest instead of importing, to enter it manually by typing it yourself.
7. To Type Manually: Click Enter a different way or Change how I enter my form at the bottom, then select 1099-INT.
8. Step 6: Enter the amount from Box 1 (Taxable Interest) and any other boxes filled on your form (like Box 4 for federal tax withheld).

2. Reporting Social Security (Form SSA-1099)

TurboTax calculates how much of your Social Security is taxed (which can range from 0% to 85% depending on your other income). In your case, I doubt you have taxable income.

Step 1: In the same Federal/Wages & Income area, scroll down to the Retirement Plans and Social Security section. 

Step 2: Click Start or Revisit next to Social Security (SSA-1099, RRB-1099).

Step 3: On the screen "Did you receive Social Security benefits?" select Yes.

Step 4: Choose SSA-1099 (unless you have Railroad Retirement, which is RRB-1099).

Step 5: Enter the amounts exactly as they appear on your form:

• Box 3: Description of Amount (Gross Benefits).
• Box 5: Net Benefits for 2025.
• Box 6: Voluntary Federal Income Tax Withheld (if any).

[NCperson]

@jpgoodsell suggest reviewing the IRS rules about who needs to file. 

Normally, someone with only $600 of interest income is not required to file a tax return. 

https://www.irs.gov/help/ita/do-i-need-to-file-a-tax-return