The Hyralan sector was a region of space.

In 2370, this sector was the rendezvous point for the mercenary ship commanded by Arctus Baran and the Klingon Toron-class shuttle of Koral. However, the USS Enterprise-D intercepted Koral's shuttle before Baran arrived. (TNG: "Gambit, Part II")

This sector might possibly be named after the star Hyralan, in the Beta Quadrant.
According to the script, the pronunciation for Hyralan was "HI-rah-lon". [1]
According to Star Trek: Star Charts (p. 66), the Hyralan sector was home to a chain of outposts, codenamed "Quebec", used by the Federation for monitoring the Romulan Neutral Zone.