District 3 features some of the best of what Santa Clara County has to offer. To the south, the district's boundary encompasses the Evergreen area then runs east stretching all the way to Stanislaus County encompassing parts of Joseph D. Grant County Park.
The boundary turns north and continues along the ridge of the spectacular Diablo Mountain Range to the ‘four corners' – an area where the counties of Santa Clara, Stanislaus, San Juaquin and Alameda meet. Along the way, the district covers the areas of Mount Hamilton, the Alum Rock – East Foothills, Milpitas, and Ed Levin County Park. District 3 reaches 4,216 feet of elevation at the peak of Mount Hamilton. On clear days, Yosemite National Park is visible on the summit. Ed Levin County Park lies in the Diablo Range, which is home to Tule Elk, California Condors, Golden Eagles, and Mountain Lions.
The north boundary parallels the San Juaquin and Alameda County lines as the San Francisco Bay meets the shores of Santa Clara County in Alviso, a true gem of District 3. Alviso Marina County Park is home to harbor seals, gray fox, hundreds of species of birds, and several threatened and endangered species. The park also offers boat tours showcasing the southern gateway to the bay. This area of the district boasts the Don Edward San Francisco Bay National Wildlife Refuge.
The district's west boundary zig zags down the center of the county to include North Valley, North San Jose, and Sunnyvale.