It is first seen when Sam and Dean get a call from Ellen and go investigate the place. When they arrive they are attacked by Ellen and Jo.
The bar serves as a regular regrouping station for the Winchester Brothers, where they pick up cases to work from Ellen and visit with the Harvelles and the other primary resident of the Roadhouse, Ash, who is technologically savvy and helps the Winchesters on a number of jobs when requested.
Unfortunately, the Roadhouse is destroyed in an attack by Azazel's minions after Ash discovers the truth of the Devil's Gate and its relation to Sam's disappearance near the end of Season 2. Though it was burned to the ground (resulting in Ash's death alongside all others inside at the time), Ellen and Jo miraculously were not there when Azazel's cohorts destroyed it. It is later seen once again in Ash's representation of Heaven in Season 5's Dark Side of the Moon, which reveals that Ash was happiest in life at the Roadhouse, and that he will now reside there for eternity in Heaven.
- Kripke didn't like the idea of Dean and Sam having a home base, so its destruction was necessary.