It appears King Boots (actually King Exotic Boots) are sold by a company at 7543 Rosecrans Ave, Paramount, California. They have a Facebook page with links to catalogs that are in Spanish. So my guess is they are made in Mexico or Central America and are popular with Vaqueros. See link
: I must be falling behind because recently I've come across two brands of cowboy boots I've never heard of: King Boots and Fenoglio. The last, Fenoglio, are made in Nocona, TX in the old Nocona Boots factory building. I found King brand boots on yehawcowboy.com and vaqueroboots.com. Fenoglio has their own web site at fenoglioboot.com. There is a video about the company on youtube but it comes off as rather misleading about the company's history.