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Erratic rock hike

From Oregon Hikers Field Guide

On the rock, Erratic Rock State Natural Site (bobcat)
Trail to the rock, Erratic Rock State Natural Site (bobcat)
View from the rock in winter, Erratic Rock State Natural Site (bobcat)
The short trail to the Bellevue Erratic (bobcat) Courtesy: Google Maps
  • Start point: Erratic Rock TrailheadRoad.JPG
  • End Point: Erratic Rock
  • Trail Log:
  • Hike Type: In and out
  • Distance: 0.5 miles
  • Elevation gain: 110 feet
  • High Point: 295 feet
  • Difficulty: Easy
  • Seasons: All year
  • Family Friendly: Yes
  • Backpackable: No
  • Crowded: No



At various times towards the end of the last Ice Age, a cycle of massive floods, known as the Missoula or Bretz Floods (named after the geologist J. Harlen Bretz) hurtled at 60 mph down the course of the Columbia River all the way to the Pacific Ocean. These floods, perhaps up to 100 of them between 15,000 - 18,000 years ago, came as huge ice dams gave way at the end of the Ice Age and massive amounts of meltwater from the continental ice sheet were released. The floods scoured away topsoil, carved valleys, and deposited sediments all along their course, but also transported large icebergs, some of them rafting massive boulders. One such raft, perhaps one of the largest, came to rest on a small prominence in what is now Yamhill County as the floods filled the Willamette Valley. This iceberg had a passenger, the so-called Bellevue Erratic, a massive boulder transported from the Canadian Rockies which presides over expansive views of Oregon's wine country from the Erratic Rock State Natural Site (For another walk that includes Ice Age erratics, see the Fields Bridge Hike}.

A sign at the trailhead gives the history of the 90-ton argillite metamorphic rock. After being picked at by generations of decidedly un-classy visitors eager for a souvenir, it is a mere remnant of the 160 tons that settlers discovered. The paved trail leads a quarter mile uphill between fences. It is a bucolic scene: blackberries and fields are on the right, a vineyard on the left. The trail turns uphill to the left under an old, sapsucker-riddled apple tree. In the fall and winter, robins and other hungry passerines flock to gorge on the rotting fruit. Now pass a Christmas tree farm on the right. At the top of this low hillock, there’s a picnic table, the remains of the rock, and views across Yamhill County farmlands all the way to Mount Hood in the east. Muddy Hill and its toupée of oaks rises behind.

For a downloadable map of the flood depths and glacial erratic locations throughout the Willamette Valley, see this site:

Fees, Regulations, etc.

  • No fee
  • Dogs on leash
  • Interpretive sign


Trip Reports

Related Discussions / Q&A

Guidebooks that cover this hike

  • Hiking Oregon's Geology by Ellen Morris Bishop
  • Wild in the Willamette edited by Lorraine Anderson with Abby Phillips Metzger
  • Oregon State Parks: A Complete Recreation Guide by Jan Bannan

More Links

Page Contributors

Oregon Hikers Field Guide is built as a collaborative effort by its user community. While we make every effort to fact-check, information found here should be considered anecdotal. You should cross-check against other references before planning a hike. Trail routing and conditions are subject to change. Please contact us if you notice errors on this page.

Hiking is a potentially risky activity, and the entire risk for users of this field guide is assumed by the user, and in no event shall Trailkeepers of Oregon be liable for any injury or damages suffered as a result of relying on content in this field guide. All content posted on the field guide becomes the property of Trailkeepers of Oregon, and may not be used without permission.