The Painted Hills unit of the John Day Fossil Beds National Monument is about 9 miles (14 km) northwest of Mitchell.

[5] At the request of William "Brawdie" Johnson, a blacksmith, a post office was established at Mitchell in 1873.

[7] Over the next two decades, Mitchell grew to include a store, assay office, two churches, two hotels, a livery stable, three houses of ill-repute (one of which is still standing), five saloons, a flour mill, and an apothecary.

The business district, including the saloons, grew up along Bridge Creek and became known locally as "Tiger Town".

The church and most of the city's homes were built at higher elevation on a bench overlooking the creek; this part of town was known locally as "Piety Hill".

[7] Since its founding, Mitchell has experienced three catastrophic flash floods along Bridge Creek, which runs through the center of the city.

An observer from the United States Geological Survey estimated that about 4 inches (10 cm) of rain had fallen in about 50 minutes at the storm's center.

[10] In 2018, a geologist from the University of Oregon found a fossilized toe of a plant-eating dinosaur near Mitchell, where the Pacific Ocean coast lay 100 million years ago.

[11] A competing claim involves fossil fragments of a hadrosaur or duck-billed dinosaur found in the Otter Point Formation near the mouth of the Rogue River.

It flows through Mitchell and then north through the Painted Hills to the John Day River.

[15] According to the United States Census Bureau, the city has a total area of 1.26 square miles (3.26 km2), all of it land.

[16] Precipitation in the region is limited by the rain shadow effect of the Cascade Range and the Ochoco Mountains to the west.

Instead of being cleared, the town is sealed and is turned into the K-9 Urban Warfare school, where military dogs are trained with live zombies.