The yellows, golds, blacks, and reds of the Painted Hills change in tone and hues depending on the time of day and the light and moisture levels. The changes can significantly affect the tones and hues of the hills. In the spring the yellow and purple wildflowers that grow in drainages and sluices of the hills, bringing further colour.
The Painted Hills Unit is located about nine miles North-West of the town of Mitchell, Oregon. Distinguished by varied stripes of red, tan, orange, and black, this area preserves a sequence of past climate change. The Painted Hills also contains a diverse assemblage of leaf fossils ageing 39-30 million years old.