Erratic Rock State Natural Site

Erratic Rock State Natural Site is a geological park in Willamette Valley, Oregon, featuring a massive 40-ton rock sitting on a 250-foot hill surrounded by vineyards and farmland. From the top, visitors can see across to the Oregon Coast Range and the surrounding agricultural landscape.

The rock traveled over 500 miles from Canada during the Ice Age, between 12,000 and 17,000 years ago, carried by icebergs through Montana and Washington. This movement was part of the massive floods that reshaped the Pacific Northwest landscape.

The rock's name reflects how people understand this unusual formation in the landscape as a glacial erratic, a boulder found far from its source. Its presence among vineyards and farms makes it a point of local interest and curiosity for both visitors and residents of the region.

The rock is reached via a paved trail about 0.2 miles long starting from the parking area on SW Oldsville Road near Oregon Route 18. Access is straightforward and the walk takes only a few minutes for most visitors.

The rock is estimated to be around 600 million years old and originated from an ancient sea floor, making it one of the oldest objects at this site. It remains the largest erratic of its kind in Willamette Valley, demonstrating the tremendous power of glacial forces to move such massive material across such distances.

Location: Oregon

Website: https://stateparks.oregon.gov/index.cfm?do=park.profile&parkId=96

GPS coordinates: 45.14010,-123.29300

Latest update: December 9, 2025 18:43