The destination, which will take weeks to reach, is called "Solander Point," and offers Opportunity access to a much taller stack of geological layering than the area where the rover has worked for the past 20 months, the space agency reported Friday.
Both Solander Point and the rover's previous location, "Cape York," are raised segments of the western rim of Endeavour Crater, which is about 14 miles in diameter.
"Getting to Solander Point will be like walking up to a road cut where you see a cross section of the rock layers," Ray Arvidson of Washington University, St. Louis, deputy principal investigator for the mission, said.
The ground is tilted toward the north, which is favorable for the solar-powered rover to stay active and mobile through the coming Martian southern-hemisphere winter, researchers said.
"We're heading to a 15-degree north-facing slope with a goal of getting there well before winter," project manager John Callas of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said.
Opportunity and its twin rover Spirit landed on Mars in January 2004. Spirit ceased operations during its fourth Martian winter, in 2010.
Opportunity shows symptoms of aging, NASA said, such as loss of motion in some joints, but is still accomplishing groundbreaking exploration and science.