A specimen of the North American species Quercus rubra L., which is new for the flora of Karelia, has been found in the Petrozavodsk City environs. The plant is obviously an escapee. The article provides information on the location of the new record as well as facts on the distribution and invasiveness status of the species in regions neighboring Karelia, in Northern Europe. The habitat is briefly described in comparison with the native environment. Our finding of Quercus rubra is the northernmost record of this species as an escapee in Eastern Fennoscandia. The alien is considered to be a long-lived ephemeral plant.