The Gray-crowned Rosy Finch (Leucosticte tephrocotis) occurs throughout the Pacific states of North America in alpine habitat with suitable cliffs. One small “island” of such habitat, Lassen Peak in northeastern California, has never been reported to support the species despite considerable ornithological survey (Grinnell et al. 1930, Johnson 1975 and others). I and others have made a number of observations indicating that the species has recently colonized the Lassen area. This area is of particular interest because volcanism modified the habitat during eruptions between 1914 and 1921, and the area lies between the major ranges of the two well-marked subspecies L. t. littoralis and L. t. dawsoni. The purposes of this paper are to review previous surveys of the area, to report and discuss recent records, to document breeding status and subspecies identity, and to suggest causes of recent colonization.