In 1860, a letter from New York to California took three weeks by stagecoach, longer by ship around Cape Horn. The country was three months from electing Lincoln and twelve from civil war. California — gold, ports, half a million people — was effectively unreachable in real time.

Three freight men in Leavenworth, Kansas — William Russell, Alexander Majors, William Waddell — proposed something close to delusional. Ten days, end to end. Five hundred horses. A relay of riders moving day and night across two thousand miles of plains, mountain, and desert.

The mochila — a leather mail pouch designed to slip from saddle to saddle in seconds — was loaded at the Pikes Peak Stables. The first rider out, by most accounts, was Johnny Fry. Some say Billy Richardson. The records of the first night are themselves part of the legend.

The horse was led down to the Missouri River ferry. Across, into Kansas Territory. By morning, the mail had crossed two hundred and fifty miles of plain. Behind it, the second rider. Behind that one, the third.

Out of the Missouri bottom and into the Flint Hills. The Big Blue River. Marysville, then northwest into present-day Nebraska, picking up the Little Blue and finally the Platte — the Pony Express's great east-west highway.

Riders rode in shifts of seventy-five to a hundred miles, swapping horses every ten or twelve. A swing station was sometimes a sod hut and a corral. A home station was where you ate and slept until the eastbound mail came through.

Fort Kearny was the first major army post on the route — a home station with company, a meal, the closest thing to civilization for hundreds of miles in any direction. The mail pulled in, the mail pulled out. Fresh horse, fresh rider, gone again.

Past Kearny, the Platte stretches west like a slow brown ribbon under a sky too big to think about. Buffalo herds, sometimes still in the millions, rolled across the route like weather. Riders learned to ride around them, never through.

Past Julesburg, the land rose. Chimney Rock appeared — a thin stone needle visible for two days' ride in either direction, a landmark that emigrants used to chart their progress for a generation. Then Scotts Bluff. Then Fort Laramie, the great waystation of the trans-continental West.

Beyond Laramie, the trail turned hard for the high country. The Sweetwater. Independence Rock. The rise toward South Pass.

The Continental Divide, at 7,400 feet, broad and almost gentle — the only place in the Rockies where wagon trains, emigrants, and now Pony Express riders could cross without the country trying to kill them. From the saddle, a rider couldn't always tell when he had crossed it. The water, though, knew. East of the pass, every creek ran to the Atlantic. West of it, every creek ran to the Pacific.

Down toward Fort Bridger. Then southwest, into the Wasatch. Then down the long descent into the valley of the Great Salt Lake.

The largest home station on the route. The single place along the entire trail where a Pony Express rider could expect a hot meal, a real bed, and the sight of more than a dozen people. The Mormon settlement was thirteen years old. Brigham Young had picked it for its inaccessibility, and the Pony Express had just made that inaccessibility a little less true.

West of Salt Lake, the country emptied out completely. Ahead lay the Great Basin — the most punishing thousand miles on the route.

In May of 1860, six weeks into the run, a war broke out across the entire central section of the route. The Paiute, retaliating against settler violence on the Carson River, attacked stations from Carson Sink to Ruby Valley. Eight stations burned. At least sixteen station men killed. The mail kept moving anyway.

One rider, "Pony Bob" Haslam, finding his relief station burned and the next rider dead, rode on. He covered three hundred and seventy miles in just over a day and a half — through hostile country, on relays of exhausted horses, with a wounded jaw — and delivered the mail. It is, by some measures, the longest documented sustained ride in American history.

The young Samuel Clemens, traveling west by stagecoach in the summer of 1861, watched a Pony Express rider pass his coach. Years later, in Roughing It , he gave it the most quoted description anyone has ever written:

The hardest hundred miles of the route, and the last of them. The Sierra Nevada in summer is a steep grind. In winter it is something else — riders in snowshoes leading horses up Echo Summit when drifts swallowed the trail entirely. The legend includes more than one rider who dismounted, wrapped the mochila in his coat, and walked the last mile.

Down the western slope. Past Friday's Station. Strawberry. Hangtown — Placerville. The country opened. The air thickened. The mail had reached California.

The B.F. Hastings Building. A small crowd, sometimes; on the very first ride, a brass band, fireworks, and most of the city. The mochila came off its last horse at half past five in the afternoon. From there a steamer carried the mail down the Sacramento River to San Francisco overnight.

Total elapsed time on that first run: nine days, twenty-three hours. The fastest was a special run carrying Lincoln's first inaugural address — seven days, seventeen hours.