On his second exploring trip, John C. FrÉmont had worked his way south over the Nevada desert until at last he crossed the mountains and found himself in the valley of the Sacramento. Here in 1844 a small group of Americans had already been established for several years. Mexican California was scantily inhabited and was so far from the inefficient central government that the province had almost fallen away of its own weight. John A. Sutter, a Swiss of American proclivities, was the magnate of the Sacramento region, whence he dispensed a liberal hospitality to the Pathfinder's party.

In 1845, FrÉmont started on his third trip, this time entering California by a southern route and finding himself at Sutter's early in 1846. In some respects his detachment of engineers had the appearance of a filibustering party from the start. When it crossed the Rockies, it began to trespass upon the territory belonging to Mexico, with whom the United States was yet at peace. Whether the explorer was actually instructed to detach California from Mexico, or whether he only imagined that such action would be approved at home, is likely never to be explained. Naval officers on the Pacific were already under orders in the event of war to seize California at once; and Polk was from the start ambitious to round out the American territory on the Southwest. The Americans in the Sacramento were at variance with their Mexican neighbors, who resented the steady influx of foreign blood. Between 1842 and 1846 their numbers had rapidly increased. And in June, 1846, certain of them, professing to believe that they were to be attacked, seized the Mexican village of Sonoma and broke out the colors of what they called their Bear Flag Republic. FrÉmont, near at hand, countenanced and supported their act, if he did not suggest it.

The news of actual war reached the Pacific shortly after the American population in California had begun its little revolution. FrÉmont was in his glory for a time as the responsible head of American power in the province. Naval commanders under their own orders coÖperated along the coast so effectively that Kearny, with his army of the West, learned that the conquest was substantially complete, soon after he left Santa FÉ, and was able to send most of his own force back. California fell into American hands almost without a struggle, leaving the invaders in possession early in 1847. In January of that year the little village of Yerba Buena was rebaptized San Francisco, while the American occupants began the sale of lots along the water front and the construction of a great seaport.

The relations of Oregon and California to the occupation of the West were much the same in 1847. Both had been coveted by the United States. Both had now been acquired in fact. Oregon had come first because it was most easily reached by the great trail, and because it had no considerable body of foreign inhabitants to resist invasion. It was, under the old agreement for joint occupation, a free field for colonization. But California had been the territory of Mexico and was occupied by a strange population. In the early forties there were from 4000 to 6000 Mexicans and Spaniards in the province, living the easy agricultural life of the Spanish colonist. The missions and the Indians had decayed during the past generation. The population was light hearted and generous. It quarrelled loudly, but had the Latin-American knack for bloodless revolutions. It was partly Americanized by long association with those trappers who had visited it since the twenties, and the settlers who had begun in the late thirties. But as an occupied foreign territory it had not invited American colonization as Oregon had done. Hence the Oregon movement had been going on three or four years before any considerable bodies of emigrants broke away from the trail, near Salt Lake, and sought out homes in California. If war had not come, American immigration into California would have progressed after 1846 quite as rapidly as the Mexican authorities would have allowed. As it was, the actual conquest removed the barrier, so that California migration in 1846 and 1847 rivalled that to Oregon under the ordinary stimulus of the westward movement. The settlement of the Mormons at Salt Lake developed a much-needed outfitting post at the head of the most perilous section of the California trail. Both Mormons and Californians profited by its traffic.

With respect to California, the treaty which closed the Mexican War merely recognized an accomplished fact. By right of conquest California had changed hands. None can doubt that Mexico here paid the penalty under that organic law of politics which forbids a nation to sit still when others are moving. In no conceivable way could the occupation of California have been prevented, and if the war over Texas had not come in 1846, a war over California must shortly have occurred. By the treaty of Guadalupe-Hidalgo Mexico relinquished the territory which she had never been able to develop, and made way for the erection of the new America on the Pacific.

Most notable among the ante-bellum pioneers in California was John A. Sutter, whose establishment on the Sacramento had been a centre of the new life. Upon a large grant from the Mexican government he had erected his adobe buildings in the usual semi-fortified style that distinguished the isolated ranch. He was ready for trade, or agriculture, or war if need be, possessing within his own domain equipment for the ordinary simple manufactures and supplies. As his ranch prospered, and as Americans increased in San Francisco and on the Sacramento, the prospects of Sutter steadily improved. In 1847 he made ready to reap an additional share of profit from the boom by building a sawmill on his estate. Among his men there had been for some months a shiftless jack-of-all-trades, James W. Marshall, who had been chiefly carpenter while in Sutter's employ. In the summer of 1847 Marshall was sent out to find a place where timber and water-power should be near enough together to make a profitable mill site. He found his spot on the south bank of the American, which is a tributary of the Sacramento, some forty-five miles northeast of Sacramento.

In the autumn of the year Sutter and Marshall came to their agreement by which the former was to furnish all supplies and the latter was to build the mill and operate it on shares. Construction was begun before the year ended, and was substantially completed in January, 1848. Experience showed the amateur constructor that his mill-race was too shallow. To remedy this he started the practice of turning the river into it by night to wash out earth and deepen the channel. Here it was that after one of these flushings, toward the end of January, he picked up glittering flakes which looked to him like gold. With his first find, Marshall hurried off to Sutter, at the ranch. Together they tested the flakes in the apothecary's shop, proving the reality of the discovery before returning to the mill to prospect more fully.

For Sutter the discovery was a calamity. None could tell how large the field might be, but he saw clearly that once the news of the find got abroad, the whole population would rush madly to the diggings. His ranch, the mill, and a new mill which was under way, all needed labor. But none would work for hire with free gold to be had for the taking. The discoverers agreed to keep their secret for six weeks, but the news leaked out, carried off all Sutter's hands in a few days, and reached even to San Francisco in the form of rumor before February was over. A new force had appeared to change the balance of the West and to excite the whole United States.

The rush to the gold fields falls naturally into two parts: the earlier including the population of California, near enough to hear of the find and get to the diggings in 1848. The later came from all the world, but could not start until the news had percolated by devious and tedious courses to centres of population thousands of miles away. The movement within California started in March and April.

Further prospecting showed that over large areas around the American and Sacramento rivers free gold could be obtained by the simple processes of placer mining. A wooden cradle operated by six or eight men was the most profitable tool, but a tin dishpan would do in an emergency. San Francisco was sceptical when the rumor reached it, and was not excited even by the first of April, but as nuggets and bags of dust appeared in quantity, the doubters turned to enthusiasts. Farms were abandoned, town houses were deserted, stores were closed, while every able-bodied man tramped off to the north to try his luck. The city which had flourished and expanded since the beginning of 1847 became an empty shell before May was over. Its newspaper is mute witness of the desertion, lapsing into silence for a month after May 29th because its hands had disappeared. Farther south in California the news spread as spring advanced, turning by June nearly every face toward Sacramento.

The public authorities took cognizance of the find during the summer. It was forced upon them by the wholesale desertions of troops who could not stand the strain. Both Consul Larkin and Governor Mason, who represented the sovereignty of the United States, visited the scenes in person and described the situation in their official letters home. The former got his news off to the Secretary of State by the 1st of June; the latter wrote on August 17; together they became the authoritative messengers that confirmed the rumors to the world, when Polk published some of their documents in his message to Congress in December, 1848. The rumors had reached the East as early as September, but now, writes Bancroft, "delirium seized upon the community."

How to get to California became a great popular question in the winter of 1848–1849. The public mind was well prepared for long migrations through the news of Pacific pioneers which had filled the journals for at least six years. Route, time, method, and cost were all to be considered. Migration, of a sort, began at once.

Land and water offered a choice of ways to California. The former route was now closed for the winter and could not be used until spring should produce her crop of necessary pasturage. But the impetuous and the well-to-do could start immediately by sea. All along the seaboard enterprising ship-owners announced sailings for California, by the Horn or by the shorter Isthmian route. Retired hulks were called again into commission for the purpose. Fares were extortionate, but many were willing to pay for speed. Before the discovery, Congress had arranged for a postal service, via Panama, and the Pacific Mail Steamship Company had been organized to work the contracts. The California had left New York in the fall of 1848 to run on the western end of the route. It had sailed without passengers, but, meeting the news of gold on the South American coast, had begun to load up at Latin ports. When it reached Panama, a crowd of clamorous emigrants, many times beyond its capacity, awaited its coming and quarrelled over its accommodations. On February 28, 1849, it reached San Francisco at last, starting the influx from the world at large.

The water route was too costly for most of the gold-seekers, who were forced to wait for spring, when the trails would be open. Various routes then guided them, through Mexico and Texas, but most of all they crowded once more the great Platte trail. Oregon migration and the Mormon flight had familiarized this route to all the world. For its first stages it was "already broad and well beaten as any turnpike in our country."

The usual crowd, which every May for several years had brought to the Missouri River crossings around Fort Leavenworth, was reËnforced in 1849 and swollen almost beyond recognition. A rifle regiment of regulars was there, bound for Forts Laramie and Hall to erect new frontier posts. Lieutenant Stansbury was there, gathering his surveying party which was to prospect for a railway route to Salt Lake. By thousands and tens of thousands others came, tempted by the call of gold. This was the cheap and popular route. Every western farmer was ready to start, with his own wagons and his own stock. The townsman could easily buy the simple equipment of the plains. The poor could work their way, driving cattle for the better-off. Through inexperience and congestion the journey was likely to be hard, but any one might undertake it. Niles reported in June that up to May 18, 2850 wagons had crossed the river at St. Joseph, and 1500 more at the other ferries.

Familiarity had done much to divest the overland journey of its terrors. We hear in this, and even in earlier years, of a sort of plains travel de luxe, of wagons "fitted up so as to be secure from the weather and ... the women knitting and sewing, for all the world as if in their ordinary farm-houses." Stansbury, hurrying out in June and overtaking the trains, was impressed with the picturesque character of the emigrants and their equipment. "We have been in company with multitudes of emigrants the whole day," he wrote on June 12. "The road has been lined to a long extent with their wagons, whose white covers, glittering in the sunlight, resembled, at a distance, ships upon the ocean.... We passed also an old Dutchman, with an immense wagon, drawn by six yoke of cattle, and loaded with household furniture. Behind followed a covered cart containing the wife, driving herself, and a host of babies—the whole bound to the land of promise, of the distance to which, however, they seemed to have not the most remote idea. To the tail of the cart was attached a large chicken-coop, full of fowls; two milch-cows followed, and next came an old mare, upon the back of which was perched a little, brown-faced, barefooted girl, not more than seven years old, while a small sucking colt brought up the rear." Travellers eastward bound, meeting the procession, reported the hundreds and thousands whom they met. The organization of the trains was not unlike that of the Oregonians and the Mormons, though generally less formal than either of these. The wagons were commonly grouped in companies for protection, little needed, since the Indians were at peace during most of 1849. At nightfall the long columns came to rest and worked their wagons into the corral which was the typical plains encampment. To form this the wagons were ranged in a large circle, each with its tongue overlapping the vehicle ahead, and each fastened to the next with the brake or yoke chains. An opening at one end allowed for driving in the stock, which could here be protected from stampede or Indian theft. In emergency the circle of wagons formed a fortress strong enough to turn aside ordinary Indian attacks. When the companies had been on the road for a few weeks the forming of the corral became an easy military manoeuvre. The itinerant circus is to-day the thing most like the fleet of prairie schooners.

The emigration of the forty-niners was attended by worse sufferings than the trail had yet known. Cholera broke out among the trains at the start. It stayed by them, lining the road with nearly five thousand graves, until they reached the hills beyond Fort Laramie. The price of inexperience, too, had to be paid. Wagons broke down and stock died. The wreckage along the trail bore witness to this. On July 27, Stansbury observed: "To-day we find additional and melancholy evidence of the difficulties encountered by those who are ahead of us. Before halting at noon, we passed eleven wagons that had been broken up, the spokes of the wheels taken to make pack-saddles, and the rest burned or otherwise destroyed. The road has been literally strewn with articles that have been thrown away. Bar-iron and steel, large blacksmiths' anvils and bellows, crowbars, drills, augers, gold-washers, chisels, axes, lead, trunks, spades, ploughs, large grindstones, baking-ovens, cooking-stoves without number, kegs, barrels, harness, clothing, bacon, and beans, were found along the road in pretty much the order in which they have been here enumerated. The carcasses of eight oxen, lying in one heap by the roadside, this morning, explained a part of the trouble." In twenty-four miles he passed seventeen abandoned wagons and twenty-seven dead oxen.

Beyond Fort Hall, with the journey half done, came the worst perils. In the dust and heat of the Humboldt Valley, stock literally faded away, so that thousands had to turn back to refuge at Salt Lake, or were forced on foot to struggle with thirst and starvation.

The number of the overland emigrants can never be told with accuracy. Perhaps the truest estimate is that of the great California historian who counts it that, in 1849, 42,000 crossed the continent and reached the gold fields.

It was a mixed multitude that found itself in California after July, 1849, when the overland folk began to arrive. All countries and all stations in society had contributed to fill the ranks of the 100,000 or more whites who were there in the end of the year. The farmer, the amateur prospector, and the professional gambler mingled in the crowd. Loose women plied their trade without rebuke. Those who had come by sea contained an over-share of the undesirable element that proposed to live upon the recklessness and vices of the miners. The overland emigrants were largely of farmer stock; whether they had possessed frontier experience or not before the start, the 3000-mile journey toughened and seasoned all who reached California. Nearly all possessed the essential virtues of strength, boldness, and initiative.

The experience of Oregon might point to the future of California when its strenuous population arrived upon the unprepared community. The Mexican government had been ejected by war. A military government erected by the United States still held its temporary sway, but felt out of place as the controlling power over a civilian American population. The new inhabitants were much in need of law, and had the American dislike for military authority. Immediately Congress was petitioned to form a territorial government for the new El Dorado. But Congress was preoccupied with the relations of slavery and freedom in the Southwest during its session of 1848–1849. It adjourned with nothing done for California. The mining population was irritated but not deeply troubled by this neglect. It had already organized its miners' courts and begun to execute summary justice in emergencies. It was quite able and willing to act upon the suggestion of its administrative officers and erect its state government without the consent of Congress. The military governor called the popular convention; the constitution framed during September, 1849, was ratified by popular vote on November 13; a few days later Governor Riley surrendered his authority into the hands of the elected governor, Burnett, and the officials of the new state. All this was done spontaneously and easily. There was no sanction in law for California until Congress admitted it in September, 1850, receiving as one of its first senators, John C. FrÉmont.

The year 1850 saw the great compromise upon slavery in the Southwest, a compromise made necessary by the appearance on the Pacific of a new America. The "call of the West and the lust for gold" had done their work in creating a new centre of life beyond the quondam desert.

The census of 1850 revealed something of the nature of this population. Probably 125,000 whites, though it was difficult to count them and impossible to secure absolute accuracy, were found in Oregon and California. Nine-tenths of these were in the latter colony. More than 11,000 were found in the settlements around Great Salt Lake. Not many more than 3000 Americans were scattered among the Mexican population along the Rio Grande. The great trails had seen most of these home-seekers marching westward over the desert and across the Indian frontier which in the blindness of statecraft had been completed for all time in 1840.