Metron space was the territorial region of space claimed by the Metrons. This region was located somewhere in the Alpha or Beta Quadrant. The solar system at 2466 PM was within this space.
In 2267, the USS Enterprise pursued a Gorn starship into this space. The Metrons ended the pursuit, forcing a resolution to the conflict which preceded this pursuit. (TOS: "Arena")
This region might have an association with the Metron Consortium.
In Star Trek: Star Charts (p. 64) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Metron Consortium was the name of the Metrons' interstellar nation. This nation was located in the Beta Quadrant.