Larkin acquired several land grants including Rancho Jimeno, Rancho Boga, Rancho Cienega del Gabilan, Rancho Pleyto, Rancho Cotate, and Rancho Larkin’s Children. In his last years, Larkin engaged in land speculation and was thought by some to be the richest man in America. On October 27, 1858, while at Colusa, California, he contracted typhoid fever and died within a week. He was buried in what was the Laurel Hill Cemetery in San Francisco, but he is now interred at Cypress Lawn Memorial Park in Colma, California.