Ellen Harvelle

Background
Ellen is the wife of Bill Harvelle and had a daughter Jo Harvelle but is now a widow since her husband's death.

Season 2
Four months prior to his death, Ellen leaves a voicemail message on John's phone saying she can help him with the demon. Sam retrieves the message and the boys travel to the Roadhouse. Ellen explains that she knew John and that he was "was like family once." While waiting for Ash to analyze John's information on the Yellow-Eyed Demon, Ellen passes on to the boys a case she was "saving for a friend".

Sam speculates as to whether Ellen and John ever "you know", but Dean thinks not.

After the boys kills the Rakshasa, they return to the Roadhouse where Ash has set up a computerized demon tracking system. Ellen invites the boys to stay, but they decline and return to Bobby's.

After encountering Gordon, Sam rings Ellen for information, and she warns him that Gordon is dangerous

Sam and Dean go to the Roadhouse for help after Sam has a vision. After dealing with Andy and his evil twin Ansem, the boys get a call from Ellen and return to the Roadhouse. She indicates she knows the boys are part of something:

... This isn't just your war, this is war. Now, something big and bad's coming and it's coming fast, and their side holds all the cards. Now, at best all we got is us. Together. No secrets or half-truths here.

Ellen is trying to prevent Jo from hunting on her own, but even though Ellen gives the case to Sam and Dean, Jo sneaks off and joins them. Despite getting Ash to help her cover her tracks, Ellen works out that Jo is in Philadelphia with the Winchesters. When she rings, Dean confesses that Jo has being kidnapped by the spirit of Dr. H.H. Holmes. Ellen flies out to Philly, and after Jo is rescued drives back in the Impala with Sam, Dean and Jo.

Back at the Roadhouse, Ellen reveals to Jo that her father was killed while hunting with John Winchester.

As he searches for the other Special Children, Sam seeks help at the Roadhouse. Ellen tells him that after they last met, Jo insisted on continuing hunting, and Ellen said "not under my roof". Ellen explains that she doesn't blame Sam and Dean.

Later Gordon reveals someone at the Roadhouse told him about Sam's powers.

Ellen turns up at Bobby's place, explaining that she was out buying pretzels when demons attacked the Roadhouse, killing everyone and burning it to the ground, however Ellen rescued Ash's research from the safe. Bobby makes her drink a shot of holy water to ensure she isn't possessed.

At the devil's gate in Wyoming Jake uses his mind powers to get Ellen to point her own gun at her head. After the gate opens, it is Ellen and Bobby her finally close it.

Season 2

 * "Everybody Loves a Clown"
 * "Bloodlust"
 * "Simon Said"
 * "No Exit"
 * "Hunted"
 * "All Hell Breaks Loose - Part 2"

Season 5

 * "Good God, Y'all"
 * "Abandon All Hope..."

Trivia

 * She runs a saloon called Harvelle's Roadhouse in Nebraska which is frequented by hunters.
 * Ellen is an old acquaintance of John Winchester's, but before his death hadn't spoken to him for a long time.
 * She is the widow of Bill Harvelle, a hunter who "had a partner on his last hunt" - John Winchester.
 * Mother of Joanna Beth.