Task: Question Generation
Input (English): Also on the north side is the suburban community of Catalina Foothills, located in the foothills of the Santa Catalina Mountains just north of the city limits. This community includes among the area's most expensive homes, sometimes multimillion-dollar estates. The Foothills area is generally defined as north of River Road, east of Oracle Road, and west of Sabino Creek. Some of the Tucson area's major resorts are located in the Catalina Foothills, including the Hacienda Del Sol, Westin La Paloma Resort, Loews Ventana Canyon Resort and Canyon Ranch Resort. La Encantada, an upscale outdoor shopping mall, is also in the Foothills.
Output (English): What is the southern edge of the Catalina Foothills area?