Since leaving the "Lewis and Clark Gap" of Marathon Valley, Opportunity has been driving through "Bitterroot valley" toward her first waypoint of the new extended mission, "Spirit Mound."

With the Sol 4500 (Sept. 20, 2016) drive, she arrived at the base of the mound. The rover then bumped to a parking position for imaging and access to possible surface targets on Sol 4502 (Sept. 22, 2016). Finally, on Sol 4505 (Sept. 25, 2016), Opportunity bumped to "Gasconade," a thin, bright and linear outcrop, another possible surface target.

The Sol 4500 uplink had to be shortened to avoid an X-band fault due to a very late X-band pass and Earth set below the highly tilted rover deck. A Quick Fine Attitude (QFA) was also done on Sol 4500.

Panoramic Camera (Pancam) images of Spirit Mound and a Navigation Camera (Navcam) panorama were done on Sol 4501 (Sept. 21, 2016), with dust devil monitoring the following morning. On Sol 4502 (Sept. 22, 2016) Pancam images of nearby boulders were taken before the drive and a post-drive Pancam mosaic of Spirit Mound was taken afterwards.

Opportunity took more color Pancam images of Spirit Mound, performed a Pancam low sun survey, and took Microscopic Imager (MI) sky flats on Sol 4503 (Sept. 23, 2016), with a Pancam horizon survey the following morning.

On Sol 4504 (Sept. 24, 2016), Opportunity took a 13-filter Pancam image of "Council Bluffs", a section of the ridge south of Gasconade, and Gasconade itself, followed by a Pancam 4x1 context panorama of the ridgeline including Council Bluffs. On Sol 4506 (Sept. 26, 2016), Opportunity collected a Navcam image of her tracks, took a Pancam image of "Portland," a breccia target, and a Pancam mosaic of the top of Spirit Mound above Gasconade.

As of Sol 4506 (Sept. 26, 2016), the solar array energy production is 474 watt-hours with an elevated atmospheric opacity (Tau) of 0.892 and a solar array dust factor of 0.701.

Total odometry as of Sol 4505 (Sept. 25, 2016) is 26.99 miles (43.44 kilometers).