Vulcan(ian) space was the territorial region of space claimed by the Vulcan High Command that surrounded the Vulcan system in the Beta Quadrant.
According to T'Pol, Paan Mokar's sole value to the Andorians was its strategic location near Vulcan space. (ENT: "Cease Fire")
In 2153, Jonathan Archer reasoned that if Enterprise NX-01 could get to Vulcan space before Klingon attackers repaired their engines, they'd "think twice about giving us anymore trouble." (ENT: "The Expanse")
The star Regulus was located adjacent to both Vulcan and Andorian space, just beyond the range of Andorian listening stations. During a planned attack on Andoria, V'Las assembled a fleet of cruisers and combat cruisers there during a planned invasion in 2155. (ENT: "Kir'Shara")