March 2018 -- Washington, DC has revised its statutory position on ferrets.  Effective as of March 30, 2018,  DC Code 8-1808 now lists ferrets among the classes of EXEMPTED animals from those that are prohibited in the District, thereby making ferrets legal to own in the District.  The Code reads:  

• (j)(1) Except as provided in this subsection, a person shall not import into the District, possess, display, offer for sale, trade, barter, exchange, or adoption, or give as a household pet, any living member of the animal kingdom, including those born or raised in captivity, except the following: ​
• (A) Domestic dogs, excluding hybrids with wolves, coyotes, or jackals;   (B) Domestic cats, excluding hybrids with ocelots or margays; (C) Domesticated rodents and rabbits; (D) Captive-bred species of common cage birds; (E) Non-venomous snakes, fish, and turtles, traditionally kept in the home for pleasure rather than for commercial purposes; (F) Ferrets;  and (G) Racing pigeons, when kept in compliance with permit requirements. ​https://code.dccouncil.us/dc/council/code/sections/8-1808.html 
• This action reverses a 36 year prohibition of ferrets, which were added to the DC code of "prohibited species" in 1982.  At the time the reason given was the lack of an approved  Rabies vaccine for ferrets.  The first Rabies vaccine for ferrets, IMRAB-3, was licensed by the United States Department of Agriculture in 1990.  However, the DC council refused to act to remove ferrets from the banned list until recently. 

October 20, 2017 - California ferret enthusiasts are exploring Sanctuary Status for their beloved pets at the city level.  On September 26, 2017, residents of La Mesa, California (in San Diego County) spoke before the City Council to request sanctuary status and a "safe harbor" for there furry friends.  Council Members were duly impressed and are in teh process of exploring the status change.  Similar efforts are being pursued in Culver City as well.