I received a 592-B statement from California from a prize I won on a game show. Where do I enter the tax deduction on my federal return?

There's no place to enter Form 592-B information on your federal return.  Enter it in the state portion of TurboTax.

To enter your Form 592-B information in TurboTax Online: 

1. Open TurboTax Online
2. Select  Tax Home in the left pane
3. On the  Hi, let's keep working on your taxes! screen, select the dropdown on the right side of the State Taxes box, then select Start, Continue, or Pick up where you left off
4. Proceed through the state screens until you come to Take a look at California credits and taxes
5. Scroll down to Payments and withholding.  Select Start or Revisit to the right of Real Estate and Other Withholding
6. Select  Yes on the Any Real Estate or Other Withholding Forms? screen
7. Proceed through the following screens, making entries as appropriate