The Oregon Vortex is a roadside attraction in Gold Hill, Oregon, notable for its presumed paranormal properties, which are caused by a fascinating and convincing optical illusion of the gravity hill type.

It is said that a gold assay office built there in 1890 slid from its foundation, coming to rest at an odd angle. (This claim is readily disputed, because the boards have been cut at odd angles unnatural for a normal house construction.) Visitors to the structure subconsciously assume that its walls are vertical and its floor level, since those rules apply to every other building they have visited. This erroneous assumption provides the illusion of a localized gravity anomaly, as objects seem to roll uphill or balance at odd angles. The same phenomenon is demonstrated in Pennsylvania's Laurel Caverns.

Many of the "paranormal events" based on visual information are well

Many believers claim that the site is truly paranormal. Some people find relief for back pain at the Vortex; others become dizzy. It is said to be at the intersection of ley lines, at the boundary of geomagnetic fields, and in an actual gravity anomaly. The effects are said to be strongest when the moon is full.

The vortex is featured in the game Sam & Max:Hit The Road, as one of the many sites to solve the mystery of the missing sideshow freaks.