The Milky Way Galaxy was split into four quadrants, a wedge-shaped measurement spreading out from the galaxy center. A quadrant was a region of space measuring 50,000 light-years by 50,000 light-years. The quadrants were positioned neither clockwise nor counterclockwise. (ST reference: Star Charts)

Other interstellar regions and smaller locations were also known as quadrants, like the Morgana Quadrant. (TNG episode: "Pen Pals")

Galactic quadrants

The four galactic quadrants were named for Greek letters. These letters were also used as visual shorthand for each quadrant. (ST reference: Star Charts) In the early 25th century, the Delta Quadrant was represented by an upper-case Delta, whereas lower-case letters were used for the three other quadrants. (STO - Klingon War mission: "Welcome to Earth Spacedock" in-game "Galaxy" map)

The Delta Quadrant was known as the "First Quadrant" by the Confederacy of the Worlds of the First Quadrant. (VOY novel: Protectors)

• Alpha Quadrant
• Beta Quadrant
• Gamma Quadrant
• Delta Quadrant

Stellar cartography key

Gamma Quadrant	Delta Quadrant
Alpha Quadrant	Beta Quadrant

History

Over eons of time, stellar drift caused star systems to move between quadrants over millions of years. (TNG - The Lost Era novel: The Buried Age)

The differentiation between galactic quadrant was in use as early as the 22nd century. In 2152, Captain Jonathan Archer advised Subcommander T'Pol that cybernetic attackers encountered by Enterprise NX-01 had sent a signal to their presumed homeworld in the Delta Quadrant. (ENT episode: "Regeneration")

Appendices

Connections

multiverse • universe • galaxy
Galactic regions:	quadrant • sector • cluster • nebula • star system
System bodies:	star • planet • planetoid • dwarf planet • moon • asteroid • meteoroid • comet

External links

• Quadrant article at Memory Alpha, the wiki for canon Star Trek.
• Sector_space article at Star Trek Online Wiki.