Unimatrix 325, Grid 006

From Memory Alpha, the free Star Trek reference

Unimatrix 325, Grid 006 is the Borg spatial designation for a region of space in the Delta Quadrant.

In 2375, a proto-nebula formed in this area, and was investigated by the USS Voyager. During that mission, the 29th century Borg drone known as One activated his proximity transceiver, attracting a nearby Borg sphere. The sphere was later destroyed inside the nebula. (VOY: "Drone")