It doesn't...It just shows it on the "Personal info summary" screen after you save your address.
Then----ignore it. The IRS is not using your county for anything that affects your refund or tax due. Your county might matter later on your state return if you enter anything about property tax or local tax paid. But you will get a screen to enter it.
Thanks!...I figured Feds don't care since it isn't on the 1040. If it asks for it when I do (OH) state taxes then all is good.
Are you entering your county in a certain place in your state return where the wrong county would affect your return? Unless you're claiming a specific County credit for tax, it most likely won't affect your return if the wrong county shows.
If you're using TurboTax Online, try clearing your Cache and Cookies and return to the entry to see if the issue resolves.