Cornelius Jensen

Cornelius Boy Jensen (September 29, 1814 – December 12, 1886) was a Danish sea captain and Californian politician. Of the nine one-year terms that he served as county supervisor between 1856 and 1877, Jensen was the chairman of the San Bernardino County Board of Supervisors four times. His Agua Mansa home, the Jensen Alvarado Ranch, is a registered California Historical Landmark (No. 943) and is listed on the National Register of Historic Places.

Early years Jensen was born on the North Frisian island of Sylt off the coast of Southern Schleswig (then part of Denmark, now in Germany) in either 1812 He took his mate's examination in Denmark

Biography Jensen was captain of his own vessel for 20 years. He arrived in San Francisco in 1848. With news of the California Gold Rush, his crew jumped ship and, thereafter, he went to Sacramento and opened a store, selling items to the gold miners. It was there that he met the Californio Ignacio Alvarado. At Alvarado's urging Jensen moved to Southern California, settling in Agua Mansa around 1854. At the age of 40, he married Alvarado's 16-year-old sister, Mercedes Alvarado (c. 1848–1914) at Mission San Gabriel in 1853.

Personal life After the Great Flood of 1862 destroyed much of the town of Agua Mansa, Jensen and his wife built a home on hundreds of acres on what was to become the Cornelius and Mercedes Jensen Ranch, a California Historical Landmark, located at the Jensen-Alvarado Ranch Historic Park and Museum. Henry (born 1867) was a member of the school board. Their son John, who married Emily Crowder, built a wood-framed home that was subsequently moved to the Jensen-Alvarado Historic Ranch and Museum, serving as the caretaker's home.