Oneamisu sectoredit this page

From Memory Alpha, the free Star Trek reference

The Oneamisu sector contains the Braslota system.

In 2365, the USS Enterprise and the USS Hathaway conducted a Starfleet battle simulation in the Braslota system. (TNG: "Peak Performance")

Presumably, this sector lies within Federation borders, but the presence of the Ferengi marauder Kreechta indicates it could have been open territory. Most of the simulation information is in-joke references to Japanese animation or anime, including The Wings of Honneamise (aka Oneamisu No Tsubasa) for this specific example.