The demographics of the Cucamonga Valley have been shifting in recent years. The population of European Americans, who once constituted a large majority, is on the decline while the population of Latinos and African Americans is growing . Unlike most of Southern California, there is not a particularly strong representation of Asian Americans in the Cucamonga Valley, although it is steadily increasing. Rancho Cucamonga has the highest population of Asian Americans in the Cucamonga Valley, at 9.0% of the population.
Historic U.S. Route 66, as Foothill Boulevard, runs east-west through the region. Other major surface streets include Base Line Road, Arrow Route, 4th Street/San Bernardino Avenue, and Valley Boulevard running east-west and Archibald Avenue, Sierra Avenue, and Riverside Avenue running north-south.