The Ross class was a variant of the Galaxy-class exploration cruiser, combining the aesthetics and innovations of both the Galaxy and Sovereign classes, as well as new technologies retrieved from the Delta Quadrant by the USS Voyager. Launched in the 2380s, spacecraft of this class remained in service into at least the the 2410s. (Star Trek Online, Clear Skies)
The lead vessel of the class, the USS Ross, was commissioned circa 2381 and assigned to field testing in the Shackleton Expanse by Admiral Naulis Rhee. (Clear Skies: "Prologue")