Valo I was the first planet in the Valo system, with at least three moons. In 2368, Bajoran resistance leader Orta maintained his hidden base on the third moon of Valo I (see unnamed moons). Based on a tip from Keeve Falor, the USS Enterprise-D traveled to Valo I and made contact with Orta, who informed them that the Bajorans were not responsible for the attack on Solarion IV. (TNG: "Ensign Ro")
According to the Star Trek: Star Charts, on page 47, Valo I was located on a boundary line, the closest to Federation space, of the Demilitarized Zone, and this planet was located in the Alpha Quadrant.