Pictured: Painted Hills & Clarno (Leaf) Fossils......100 more photos here.
I could not normally, in good conscience, recommend a hiking network that is scattered among hundreds of driving miles. John Day Fossil Beds National Monument has enough to offer and overcomes the inconvenience.
My advice, stay in Mitchell at the historic Oregon Hotel (rustic, with community shower and toilet). After early check-in go to the nearby Painted Hills. There are about 2 1/2 miles of trails and the hills are beautiful deposits, changing texture and color with the weather. Before leaving Mitchell in the morning, take another look at the hills from the overlook. (All 3 units of the park are free access.) Head for the Sheep Rock Unit (park headquarters) for a museum and maybe five miles of hiking. The Sheep Rock Unit is the "History Channel" section. Finally, drive almost 80 miles to the Clarno Unit near Fossil, Or. for two or three very short hikes. That is hard to justify, but the leaf fossils and natural arch were great.
The second day was a very long day, with 200 miles of driving plus about 6 miles of hiking, with a museum. That's why I recommend just a quick morning look at Painted Hills.
No trails in the Monument are difficult. Blue Basin Trail has a little grind involved.
This area of the Oregon desert is uncomfortable in summer and winter.
Access to Painted Hills is off of Rt. 26 west of Mitchell, Or. Sheep Rock Unit is 40 miles east on the same highway. Clarno Unit is accessed from Rt. 218, west of Fossil, Oregon.
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