I am gate locked from visiting him in the prison. He will be at the county jail for court, can I visit him there?

You might be able to get away with a county visit if their vetting procedures are not as strict. We don't know the facility you are going to, so we cannot offer anything further. If you are not permitted to visit in the prison, why would they let you visit in the county jail? Unless they don't know why you are being denied, you could try and see what happens.