Benjamin Minturn Hartshorne (1826–1900) was a California businessman who immigrated during the California Gold Rush. He was involved in Sacramento River and Colorado River steamboats as well as maritime shipping.
Born on May 7, 1826, at Highlands, New Jersey, Benjamin was the son of Robert Hartshorne. He moved to California in 1849 and became involved in the ferry business at the Yuma Crossing on the Colorado River with George Alonzo Johnson and other partners from San Francisco.
Seeing the opportunity in bringing supplies to the isolated post of Fort Yuma, Hartshorne and Johnson sold out to their other partners in the Yuma ferry and returned to San Francisco in 1852. The two men then contracted to carry supplies up the Colorado in poled barges, but this endeavor failed due to the strong current and many sandbars in the river. After a steam tug, the 20 horsepower Uncle Sam was successfully used to ascend the river in 1853, Johnson formed the George A. Johnson & Company. Hartshorne was employed as a shipping agent in San Francisco and another partner Captain Alfred H. Wilcox, who was an experienced sea captain, was taken on for his experience in the hazards of the Colorado River Delta.
The company brought the disassembled side-wheel steamboat General Jesup to the Colorado River Delta and assembled it with a more powerful 70 hp engine. There Johnson began successfully shipping cargo and carrying passengers on the Colorado River from its estuary, up to Fort Yuma. This steamboat carried 50 tons of cargo to the fort in 5 days and brought the cost to supply the fort down to $75 a ton from the $500 a ton it cost to ship cargo overland across the desert from San Diego. The route made the Company $4,000 per trip per ship in the estuary of the Colorado River.