Also known as the Corps of Discovery Expedition, the Lewis and Clark Expedition crossed the newly acquired western portion of the country after the Louisiana Purchase. This group of U.S. Army and civilian volunteers under the command of Captain Meriwether Lewis and his close friend Second Lieutenant William Clark set out from Illinois, on May 14, 1804.

They crossed the Continental Divide of the Americas near the Lemhi Pass, eventually coming to the Columbia River, and the Pacific Ocean in 1805. The return voyage ended on September 23, 1806.

Image: James Lee

The leader of the Wheeler Survey, George Montague Wheeler, was an American pioneering explorer and cartographer who led one of the major geographical surveys of the western United States in the late 19th century.

In 1872, the US Congress planned to map the portion of the country west of the 100th meridian. This plan became known as the Wheeler Survey, which lasted until 1879 when the Wheeler, King, and Powell Surveys’ combined work was reorganized as the United States Geological Survey.

Image: Alex Moliski

The Donner Party was a group of pioneers who migrated to California in a wagon train from the Midwest. Delayed by a multitude of mishaps, they spent the winter of 1846-1847 snowbound in the Sierra Nevada.

While the journey west usually took between four and six months, the Donner Party chose to follow a new route called the Hastings Cutoff, which delayed them greatly.

Image: Naithen

Mark Twain was never one to shy away from adventure. Roughing It was published in 1872. It follows his travels through the American West from 1861 to 1867, when he joined his brother Orion Clemens, appointed Secretary of the Nevada Territory, on a stagecoach journey west.

Image: Jim Strasma

The "Father of the National Parks" was a Scottish-born American explorer, naturalist, author, botanist, and early advocate for the conservation of the nation’s wilderness.

After spending much of his youth traveling across the country, Muir visited Yosemite and was enthralled by its natural beauty. Later on, he worked as a shepherd for a season in the valley, built a cabin, and began advocating for the creation of a national park to protect the area.

Image: Mathilda Khoo

Probably one of the most famous entries on this list, Jack Kerouac’s 1947 cross-country hitchhiking round-trip became the basis for On the Road, a freeform travelogue that became the bible of the Beat Generation.

His roundtrip started and ended in New York, passing through Chicago on the way out to California, following the West Coast south before returning east.

Image: Ana Viegas

In 1960, John Steinbeck decided to travel across America setting out from his Long Island home aboard his camper van, dubbed Rocinante, and accompanied by his French poodle, Charley. In 1962, he published Travels with Charley: In Search of America.

Their 10,000-mile-long trip passed through New England, then via Niagara Falls along the Canadian border, hitting Chicago and continuing to Seattle before turning south towards the Salinas Valley, then to Texas, New Orleans, and a huge chunk of the Deep South.

Image: Jack Anstey

Long before writing The Bonfire of Vanities, Tom Wolfe embarked on a trip across the country with a group of psychedelic enthusiasts known as the Merry Pranksters. The trip produced his 1968 nonfiction book, The Electric Kool-Aid Acid Test.

Image: Geio Tischler

William Least Heat-Moon lost his wife and his job as a professor in a short period of time, which prompted him to embark on a soul-searching journey across the country. The result was 1982’s Blue Highways, a novel that describes the experiences he had during his travels, including conversations with colorful characters, the towns he visited, and his adventures on the road.

Image: Aaron Huber

Imagine driving across the country with the brain of one of the world’s most celebrated geniuses in the backseat. That is exactly what Michael Paterniti experienced and shared in his 2000’s Driving Mr. Albert: A Trip Across America with Einstein’s Brain.

The author started his quest in New Jersey, driving the doctor who performed Einstein’s autopsy and afterward refused to give up the brain which, eventually, was delivered to an Einstein heir in Berkeley.

Image: Tim Trad