Channel 31 signed on the air as KFXP, the Fox affiliate for the Pocatello–Idaho Falls market, on July 16, 1998. Prior to the station's launch, Fox programming had been seen on area cable systems via Foxnet; the network also maintained a secondary affiliation with CBS affiliate KIDK (channel 3). KFXP was originally owned by a partnership of three companies—Redwood Broadcasting, Winstar Communications, and Compass Communications—that had competed for the license; through a time brokerage agreement, the station was operated by Sunbelt Communications (later known as Intermountain West Communications Company), owner of NBC outlet KPVI (channel 6), and the two stations shared studios in Pocatello. By 1999, Compass Communications had acquired Redwood and Winstar's interests in KFXP. In its early years, channel 31 had a secondary affiliation with UPN; however, this had ended by 2000.