The Martinez Regional Shoreline bounds the city to the north along the Carquinez Strait. Carquinez Strait Regional Shoreline includes the Franklin Hills west of downtown, stretching west to the unincorporated community of Port Costa and the town of Crockett. Briones Regional Park borders the Alhambra Valley to the south. Waterbird Regional Preserve and the McNabney Marsh border the city and Highway 680 to the east. Martinez's location at the east end of the Carquinez Strait as it widens to Suisun Bay includes dramatic water views stretching to the Sierra range. From surrounding ridge tops views stretch to nearby Mount Diablo, Mount Saint Helena, Mount Tamalpais, and others.