Campaign Setting

Okay, so you've decided you want to create your own world in your weekly tabletop game.

I remember when I decided to start my first Dungeons and Dragons game as a DM, and found about a month into it that I'd accidentally created my own campaign world.

There are a lot of excellent Dungeons & Dragons setting books out there that will give you all the details you need to run a game in their setting, and those settings (also known as campaign settings, world settings, campaign worlds and/or simply campaigns) are often excellent.