Cactus Rock is a rock formation in Upper Rockridge. It is located at 6240 Acacia Avenue. Oakland Geology described it as a knocker of the Franciscan Complex. A knocker is a small body of bedrock, surrounded by a matrix of softer rocks, that protrudes from the ground surface. Cactus Rock may have served as the influence for Rockridge to be named "Rock Ridge," in the late 19th century.
- "Hills covered in beautiful homes," from OaklandNorth