(covers information from several alternate timelines)
Forcas III was the origin of a drink that Guinan served in Ten Forward on the USS Enterprise-D. When Data tried this drink, during one of his first experiences with his emotion chip, he described the Forcas III drink as "revolting". (Star Trek Generations)
According to the Star Trek: Star Charts (pg. 64), the Forcas system was located in or near to Klingon space, in the Beta Quadrant. Primary was an Class K star with a magnitude of +5, which was the same brightness as Sol.