How many people need to be present on the day of a courthouse marriage? Also can you get your certificate and get married in the same day?

Genrally you need at least 5 people. The bride and groom, two witnesses and the person officiating. Some states require a waiting period between license and ceremony. Some don't.

It depends on what state and/or county you are in.

Here in Ohio, Licking County... You don't need anyone with you... Just bride and groom. The judge does the marriage, and a court officer is there.

I'm sure this can be easily answered for you. Give a quick call down to your local courthouse and ask... I'm sure they will be able to answer you more accurately in regards to where you live.