The unincorporated part encompasses those parts of the Crescenta Valley and northwestern San Rafael Hills not in the cities of Glendale or La Cañada Flintridge. Only a small portion of Montrose is unincorporated, the vast majority of it lies within the City of Glendale. Both the unincorporated area and the portion of incorporated Glendale north of Montrose are collectively called La Crescenta-Montrose.
La Crescenta-Montrose is bordered on the north by the Angeles National Forest, on the east by La Cañada Flintridge, on the south by Glendale, and the northwest by Tujunga. The Foothill Freeway runs through the southern portion of the area. According to the United States Census Bureau, the La Crescenta-Montrose area measures about 3.4 square miles (8.8 km2). The population was 19,653 at the 2010 census, up from 18,532 in the 2000 census.
