Sunnyvale's northern border meets the southern tip of the San Francisco Bay, giving the city a unique relationship with the region's aquatic ecology.
- **San Francisco Bay:** The city's shoreline features restored salt ponds and wetlands that buffer the urban environment and provide a habitat for diverse wildlife. - **Creeks and Channels:** Several urban creeks and drainage channels traverse the city, carrying rainfall from the Santa Cruz Mountains down to the Bay. Notable waterways include **Calabazas Creek**, **San Tomas Aquino Creek**, **Stevens Creek**, and the **Sunnyvale East and West Channels**. - **Guadalupe Slough:** A tidal slough bordering the northern Baylands, historically significant for the area's early maritime trade and now a protected natural area.