Opportunity is within 'Marathon Valley' on the west rim of Endeavour Crater completing a valley floor survey for clay minerals before moving to the winter location on the south side of the valley.

Low-elevation orbiter relay passes to the west have resulted in little to no data return on some relay passes. This is a function of orbit geometry and the high valley wall to the west within Marathon Valley. On Sol 4163 (Oct. 10, 2015), Opportunity drove over 33 feet (10 meters) in a dogleg maneuver, first north then east, avoiding some terrain obstacles.

The rover collected some mid-drive images of the departed location to assist analysis of some wheel/terrain interaction during the last turn in place.

On the next sol, the rover collected both Panoramic Camera (Pancam) and Navigation Camera (Navcam) panoramas and continued with the diagnostic readout of Flash Bank 7. More Pancam panoramas were taken on the sol after that.

On Sol 4166 (Oct. 13, 2015), Opportunity drove again, this time about 66 feet (20 meters) to the southeast. Afterward, more Pancam and Navcam panoramas where collected. The rover is now on some favorable northerly tilted terrain. Opportunity will remain on northerly slopes for the balance of the winter.

As of Sol 4166 (Oct. 13, 2015), the solar array energy production was 325 watt-hours with an atmospheric opacity (Tau) of 0.557 and a solar array dust factor of 0.577.

Total odometry is 26.48 miles (42.62 kilometers), more than a marathon.