New data on the distribution of Japanese white birch (Betula platyphylla Sukacz.) groves in the Olyutorsky District (Koryak Okrug of the Kamchatsky Krai) are presented. The geobotanical description of white-birch forests in the valley of River Kailulovayam, a tributary of River Vyvenka, is given. Using the dominantdeterminant approach the forests were ascribed to the association Betuletum platyphyllae fruticoso-varioherbosum. White-birch forests of the Koryak Okrug grow in the valleys of large rivers in areas away from the influence of the Bering Sea. They occupy above-floodplain terraces with mesic coarse-loam and loamy sand soils underlain by pebbles. The studied community of Betula platyphylla is similar in floral composition and structure to the shrub-forb valley white-birch forests of the Penzhinsky District of the Koryak Okrug. In comparison with Kamchatka analogues, the white-birch forests of Northern Koryakia are characterized by a reduced floral composition. The white birch grove in the Kaylulovayam River valley is the second confirmed location of Betula platyphylla in the Olyutorsky District.