The name of the hospital in Twin Peaks is Calhoun Memorial. Calhoun was the name of Mark Frost's maternal grandmother, who would tell him stories about Hazel Drew, a 20-year-old governess whose body washed ashore in New York in July 1908. Drew's still-unsolved murder was an inspiration for Laura Palmer.
Although Joan Chen assumed the role of Jocelyn "Josie" Packard, the character was originally written as an Italian woman named Giovanna Pasquialini Packard, with Isabella Rossellini slated for the role. This earlier version of the character appears in the first pilot script David Lynch and Mark Frost submitted to ABC. In this seminal draft, the series was entitled Northwest Passage.
There is an alternate International Pilot which is a self-contained version of the episode that contains twenty minutes of extra footage that solves the murder. This version was filmed for international release and also in case the show was not picked up as a series.
The population of Twin Peaks is 51,201 by request of ABC. Network executives felt that a town with a population as small as 5,120 (the original population) wasn't relatable. This was one of the few changes that the network made regarding the original pilot, according to co-creator Mark Frost.
The pilot takes place on Friday, February 24, 1989.