The Erratic Rock State Natural Site is a state park and natural area in McMinnville, Oregon. It is best known for its unique geologic feature: a 40-ton erratic rock.

Named after this natural feature, the Erratic Rock State Natural Site boasts of having a rock that is only commonly found in Canada. The rock came to the area during one prehistoric flood and got deposited in the area when the ice melted. It is the largest glacial erratic that can be found in the Willamette Valley.

Aside from the massive rock, the Erratic Rock State Natural Site is also home to a scenic trail that provides beautiful views of the Yamhill Valley Vineyards. Bird watching is also a popular past time in the park.