The "petticoats" of the title referred to the many women of the Shady Rest Hotel; in the opening sequence, it was implied that Kate Bradley's three daughters swam nude in a water tower, as their petticoats were placed over the side. The "junction" in the title refers to the fact it was situated on a train line in the country.
Set in the rural town of Hooterville, the show followed the goings-on at the Shady Rest Hotel, of which Kate Bradley (Bea Benaderet) was the proprietor. Her lazy brother Joe (Edgar Buchanan) helped her in the day-to-day running of the business, while she served as a mediator in the various minor crises that befell her daughters: Betty Jo, Bobbie Jo, and Billie Jo. The actresses portraying Betty Jo and Bobbie Jo varied over the years; Billie Jo was consistently portrayed by Linda Kaye (Henning), daughter of series creator Paul Henning.
The most unique "character" in the Petticoat Junction cast was the Hooterville Cannonball, an abbreviated steam-driven train (serviced by the above-mentioned water tower) run more like a taxi service by its engineer, Charley Pratt (Smiley Burnette) and conductor, Floyd Smoot (Rufe Davis). It was not uncommon for the men of the Cannonball to make an unscheduled stop in order to go fishing or pick fruit for Kate Bradley's menu at the Shady Rest Hotel. Occasionally, Betty Jo Bradley could be found with her hand on the Cannonball's throttle, as driving the train home from trips into town was one of her favorite pasttimes. Even the show's theme song was suggestive of a train running.
Another important nonhuman character was the unnamed canine companion of the sisters, referred to simply as "the dog". It was potrayed by "Higgins", who later went on to even greater fame later as Benji. (In the series it was implied that the dog was female as it had its own petticoat in the opening water tower scene.)
J. Homer Bedloe, played by actor Charles Lane, was vice president of the C&FW Railroad. Bedloe was a mean-spirited, yet somehow also gentle, railroad executive who visited the Shady Rest Hotel periodically attempting to find justification for ending the train service of the Hooterville Cannonball (and never succeeding).
The show benefitted greatly in its first four seasons from the very strong lead-in of The Red Skelton Show, which immediately preceeded it on Tuesday nights on CBS. In its first season it even exceeded Skelton's ratings, finishing at #4 overall for the season. The rest of its time on Tuesday nights, it remained in the Nielsen top 25.
In 1968, Bea Benaderet died of lung cancer, and in the story, Joe became the proprietor of the Shady Rest. A new role was created of an female doctor in Hooterville, and June Lockhart joined the cast to serve as a replacement of sorts for Benaderet. The ratings began to fall (it had also been moved to Saturday night, traditionally American's television's lowest-rated night, the previous year) and the show was canceled in 1970.
The show was set in the same fictional universe as the rural television comedies Green Acres, also set in Hooterville, and The Beverly Hillbillies. The shows even shared characters, and sometimes "crossed over" into each other's episodes, especially so during the shows' earlier years.