Located in the heart of Southeastern Oregon, Diamond Craters Outstanding Natural Area is known among geologists as being one of the most diverse basaltic volcanic features in the United States. For the untrained visitor, however, the area is an unassuming vista of high dessert flora and a gently rolling topography. In an effort to promote the area's significance, the Bureau of Land Management has created an informative driving tour and an information kiosk that starts between milepost 40 and 41 on Oregon Highway 205 at the junction to Diamond, Oregon. The community of Diamond was named for the distinctive cattle brand used by a prominent ranch, and the name was later shared with the nearby formation.
Of the six structural domes (West Dome, Central Dome, North Dome, South Dome, Graben Dome and Northeast Dome) created by basaltic magma approximately 25,000 years ago, several have collapsed and left craters with distinctive shapes, grades, and room for exploration. Visitors will notice the wrinkles, or crust, of what were once thin layers of molten basalt flowing around the perimeter of some craters. As the lava flowed downward, it did so in streams, evidenced by the area's network of shallow tubes. Additional formations that speak to the area's tumultuous history include the caldera of the Central Crater Complex, spatter rings, cones, and spires from steam spouts and explosions.
If you are exploring the area on foot, do so thoughtfully, both for safety and for the preservation of these geological features.
Be sure to fill up on gas before heading out to the Steens Mountain area. Year-round gas stations are in Burns and Fields, Oregon. The gas station in Frenchglen is only open during the summer months. Further, cell phone reception is virtually nonexistent in much of the area, so travel with extra provisions. If you plan to explore the area extensively, we highly recommend bringing additional, full gasoline canisters to ensure that you don't get stranded.