Bajor I was the first planet in the Bajoran system, located in the Bajor sector, a region of space in the Alpha Quadrant.
In 2372, the position and orbital path of Bajor I was illustrated on a tactical cartography map displayed in the wardroom of Deep Space 9. (DS9: "Sons of Mogh", okudagram)
"BAY-jor" was the pronunciation for this planet's name from the script pronunciation guide for "Emissary". 
The Bajoran system: The location of Bajor I
The Bajoran system: Inner system. The location of Bajor I