It's still mostly held by the Federation, but they underplay its history, for reasons that will of course be obvious to anyone who read the series.
Pacifica is located deep in the Taurus Reach (this first mentioned in Reap The Whirlwind,
if not evident beforehand from the Star Charts)
and of course that's an active Federation member which is mentioned all the time in Trek lit. Never is there mention of trouble or tension in the area - characters pop back and forth to Pacifica all the time, quite casually. So apparently at least that part of the Reach is very settled now, part of the great peaceful mass of Federation space. Cestus is located on the far boundary of the Reach, and that's another system casually mentioned and travelled to - the Reach is evidently open for business and quite safe to move though. The Ravanar System is still held by the Federation - in fact, it was first mentioned in A Time to Kill
, prior to Vanguard
being launched. The Breen were snooping around and Starfleet Special Ops captured one of their ships (this ship later showed up in Zero Sum Game
I suppose the Klingons kept the parts they'd conquered - having the Star Charts
at hand while reading Vanguard
certainly supports that assumption, but the majority seems to have remained or become Federation territory.
Between what we learn in Paths of Disharmony
about the Federation downplaying the history of the region - referring to "Gariman Sector" in particular rather than the Taurus Reach as a whole - and the fact that a "Reach" in Trek terms seems to be an unexplored region into which ships and colonists are just starting to push (Cygnus Reach, Scorpius Reach and Orion Reach have all been mentioned in 24th century Trek lit), and the Taurus Reach isn't a frontier anymore, it seems likely that the term "Taurus Reach" doesn't get used in the 24th century. The systems are stil there, of course, but the Reach is perhaps no more. And the Federation wants the whole thing forgotten.