Opportunity is exploring within 'Marathon Valley' on the rim of Endeavour crater. The rover is up on the slopes of 'Knudsen Ridge.' The primary objective is to examine specific outcrop types for evidence of clay minerals. The current objective had been to reach the surface science target 'Pvt. Joseph Whitehouse' (named after a member of the Corps of Discovery).

However, with slopes in excess of 30 degrees and some gravel terrain under the wheels, Opportunity was unable to reach the intended target. On Sol 4311 (March 10, 2016), the rover made only 3.5 inches (9 centimeters) of progress after almost 66 feet (20 meters) of commanded wheel motion.

This was the third attempt to reach this very interesting target. In the end, the team decided to abandon this target and back away. On Sol 4313 (March 12, 2016), the rover backed down from this target with a 7-foot (2-meter) drive.

Documentary imagery in both Navigation Cameras (Navcams) and Panoramic Cameras (Pancams) where collected. An overnight Alpha Particle X-ray Spectrometer (APXS) measure of atmospheric argon was also collected.

More readouts of Flash memory were performed. On Sol 4316 (March 15, 2016), the rover moved further downhill, driving about 22 feet (6.7 meters) north to set up for a longer drive towards the next science target along Knudsen Ridge.

As of Sol 4316 (March 15, 2016), the solar array energy production was 559 watt-hours with an atmospheric opacity (Tau) of 0.524 and an improved solar array dust factor of 0.760.

Total odometry is 26.51 miles (42.67 kilometers), more than a marathon.