The Igo sector was a region of space.
In early 2369, the USS Yosemite was damaged here while investigating a plasma streamer. At about the same time, two Ferengi freighters were apparently destroyed in the sector by a Cardassian warship. Though Admiral Hayes was suspicious of the Ferengi claim, she had to accept there was evidence of Cardassian weapons. If the Yosemite was attacked by the Cardassians, the admiral believed it would indicate a large-scale movement into the sector by the Cardassians. (TNG: "Realm of Fear")