In Polk's message, he confirmed some common knowledge about gold in California. "It was known that mines of the precious metals existed to a considerable extent in California at the time of its acquisition," the president noted. "Recent discoveries render it probable that these mines are more extensive and valuable than was anticipated. The accounts of the abundance of gold in that territory are of such an extraordinary character as would scarcely command belief were they not corroborated by the authentic reports of officers in the public service who have visited the mineral district and derived the facts which they detail from personal observation.
"Reluctant to credit the reports in general circulation as to the quantity of gold, the officer commanding our forces in California visited the mineral district in July last for the purpose of obtaining accurate information on the subject. His report to the War Department of the result of his examination and the facts obtained on the spot is herewith laid before Congress."
Not just a gold strike, in other words, but a lot of gold. Gold that would inspire an historic gold rush, and figure no small part in the development of California as a part of the United States, and indeed of the whole country.
But Polk knew that the value of California to the United States was much greater than any gold that might be extracted. He spoke with uncanny foresight, considering that in our time, California has, despite recent setbacks, the seventh- or eighth-largest economy in the world, counted as a separate entity -- larger than Brazil and almost as large as Italy.
"Upper California, irrespective of the vast mineral wealth recently developed there, holds at this day, in point of value and importance, to the rest of the Union the same relation that Louisiana did when that fine territory was acquired from France forty-five years ago," Polk emphasized. "Extending nearly ten degrees of latitude along the Pacific, and embracing the only safe and commodious harbors on that coast for many hundred miles, with a temperate climate and an extensive interior of fertile lands, it is scarcely possible to estimate its wealth until it shall be brought under the government of our laws and its resources fully developed.
"From its position it must command the rich commerce of China, of Asia, of the islands of the Pacific, of western Mexico, of Central America, the South American States, and of the Russian possessions bordering on that ocean. A great emporium will doubtless speedily arise on the Californian coast which may be destined to rival in importance New Orleans itself."