Martinez is the county seat for Contra Costa County
Oakley is in Contra Costa County
Contra Costa County(480) ► ADJACENT TO CONTRA COSTA COUNTY Alameda County(674) ► Marin County(249) ► Sacramento County(392) ► San Francisco City and County(722) ► San Joaquin County(142) ► Solano County(114) ► Sonoma County(163) ►
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"...what we see and have before us is
not a river, but much water in a pond."
In the spring of 1776, Lt. Colonel Jaan Bautista de Anza,
Father Pedro Font, and a small group spent four days
exploring the East Bay. They wished to . . . — — Map (db m190712) HM
The 1775-76 expedition of Juan Bautista de Anza
made this site their one hundred first camp from
Horcasitas, Sonora, Mexico. Anza brought 198
colonists, located for Spain the Presidio of San
Francisco and Mission Dolores, and explored . . . — — Map (db m190721) HM
In 1919, Colonel Robert Bradford Marshall
of the United States Geological Survey
proposed an unprecedented project
of dams, canals, and pumps to
move Delta-bound water from
California's wet north and snowy
Sierra Nevada mountains to its
arid . . . — — Map (db m190979) HM
Corcoran Lake filled the Central Valley
760,000 years ago (including where you
now stand)! It drained to the ocean at
today's Monterey Bay. Tectonic forces
plugged the outlet and tilted the
lakebed to the north 200,000 years
later. The surging . . . — — Map (db m190604) HM
Fifty Years
That's all it took for the clamshell dredge to change the
Delta from a vast wetland into the agricultural, water
delivery, and shipping hub we know today. In the late
1880s, these dredges reshaped the waterways to ease . . . — — Map (db m190314) HM
The Juan Bautista de Anza Expedition of 1775-1776 traveled with
240 settlers, soldiers, and others 1,800 miles from Sonora, Mexico
to Monterey, California. Anza then traveled with a much smaller
group to San Francisco and the East Bay to discover . . . — — Map (db m190230) HM
Far from being an ancient geological feature, our Delta is a virtual newcomer.
Imagine sunrise here 14,000 years ago.
Dawn illuminates the glacier-coated Sierra
Nevada Mountains. The San Joaquin and
Sacramento Rivers merge nearby, . . . — — Map (db m190991) HM
Picture a river running through a desert.
Now picture a desert running through a river.
The San Joaquin River once flowed
uninterrupted from high mountains,
through the arid valley bearing its name,
to the Delta. Floods enriched . . . — — Map (db m190726) HM
