Sigma Draconis I was the first planet in the Sigma Draconis planetary system. (TOS: "Spock's Brain")
According to the Star Trek: Star Charts (pgs. 19, 44), Sigma Draconis I was located in Sector 004 (Sigma Draconis sector), in the Alpha Quadrant.
Sigma Draconis I was the first planet in the Sigma Draconis planetary system. (TOS: "Spock's Brain")