When, in 2374, Rom floated the possibility that the Dominion had conquered Ferenginar, Major Kira Nerys countered that it could not have been taken without first conquering systems like Clarus and Irtok. (DS9: "Profit and Lace")
According to Star Trek: Star Charts ("United Federation of Planets I") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Clarus system was located in the Alpha Quadrant. This was a trinary system with a K-class star, a G-class star, and a M-class star. In the late 24th century, it was an independent system.