The Lewis and Clark Expedition wintered at Fort Clatsop before returning east to St. Louis in the spring of 1806. It took just over 3 weeks for the Expedition to build the fort, and it served as their camp from December 8, 1805 until their departure on March 23, 1806.
The site is now protected as part of the Lewis and Clark National and State Historical Parks, and is also known as Fort Clatsop National Memorial. A replica of the fort was constructed for the sesquicentennial in 1955 and lasted for fifty years; it was severely damaged by fire in early October 2005, weeks before Fort Clatsop's bicentennial. A new replica, more rustic and rough-hewn, was built by about 700 volunteers in 2006; it opened with a dedication ceremony that took place on December 9.
The original Fort Clatsop decayed in the wet climate of the region but was reconstructed in 1955 from sketches in the journals of William Clark. The site is currently operated by the National Park Service.
In 1803, Thomas Jefferson completed the Louisiana Purchase from France. As much of the area had not been explored by whites, Jefferson commissioned an expedition to be led by his secretary, Meriwether Lewis, along with William Clark. Jefferson set a number of goals for the expedition, most notably to determine what the land contained, including plants, animals, and natural resources. Jefferson also wanted to establish good relations with the Native Americans of the area. Additionally, Jefferson was very interested in finding a water route to the Pacific Ocean, which would have cut the travel time from the Atlantic Ocean to the Pacific Ocean considerably.
In late November of 1805, after spending a number of days in what is today the state of Washington, Lewis and Clark proposed that the Corps of Discovery move to a location along the Columbia River, based on a recommendation of the local Clatsop Indians. The group decided to vote on the matter, with everyone, including Sacagawea and York, participating. The group was given three choices: stay in Washington, and be subjected to boring diets of fish and rainy weather, move upriver, or take the advice of the Clatsop Indians and explore the area to the south of the Columbia River. The expedition decided to take the advice of the local Indians and overwhelmingly decided to explore the idea of spending the winter on the southern shore of the Columbia River.
Lewis decided to explore the area before moving the entire group. He and five men left to scout the area, leaving Clark and the rest of the group behind. Lewis became frustrated when he could not find the abundant elk that the Clatsop had talked about. In the meantime, Clark had not heard from his companion in a number of days and became increasingly worried. During Lewis' absence, the group performed a number of housekeeping tasks, including fixing their clothes from the wear they had suffered during the long and arduous journey.
Finally, Lewis returned with the news that he had found an adequate location in which to winter. On December 7, 1805, the Corps of Discovery began the short journey to the location chosen by Lewis. Upon arrival, the men split into different groups: Clark led a party to the Pacific Ocean in search of salt, while Lewis split the remaining men into two groups. One group was in charge of hunting, while the other was in charge of cutting down trees to be used in the construction of the fort.
Construction of the fort was slow, due to the incessant precipitation and unyielding wind that made working conditions less than ideal. On December 23, people started to move into the dwelling, even though it didn't yet have a roof. The next day, Christmas Eve, everyone moved in. On Christmas Day it was named "Fort Clatsop" in reference to the local Indian tribe.
The structures of Fort Clatsop were relatively simple, consisting of two buildings surrounded by large walls. All of the men lived in one structure, while Lewis, Clark, Sacagawea, her husband Toussaint Charbonneau, and their son, Jean Baptiste, stayed in the other.
The winter of 1805-1806 was very long and rainy, leading to boredom and restlessness for the Corps of Discovery. They passed the time with various activities, including hunting the abundant deer and elk in the region. The deer and elk meat spoiled quickly, but the skins were used to make clothing and moccasins. Realizing the importance of their trip, Lewis spent most of his time at Fort Clatsop documenting the journey, taking notes on the wildlife, terrain, and other features. Lewis also made maps of the area, which would be especially helpful to future settlers of the Pacific Northwest. Finally, Lewis and Clark occasionally traded with the Clatsop Indians, a tribe they had come to dislike, viewing them as untrustworthy and prone to theft.
Ultimately, the group's time along the Columbia River merely served as a place to spend the winter and recoup. The men were suffering from a number of different illnesses and conditions, including venereal diseases and respiratory problems, and felt that departing would make them all feel better.
Toward the end of the monotonous winter they spent at Fort Clatsop, the men were desperate to return east. Everyone was sick and quite restless, and the steady diet of elk was becoming unbearable. Moreover, even the elk were becoming more difficult to find. Originally, Meriwether Lewis determined the departure date would be April 1st, but it was later moved up to March 20. Ultimately, they didn't leave until two days after that due to poor weather.
In order to travel back up the Columbia and reach the mountains, the group was desperately in need of canoes. The Clatsops had a number of them, but refused to trade with Lewis and Clark. Eventually, an agreement was reached for one canoe, but Lewis decided they had no choice but to steal a second one, since they couldn't all travel without at least two boats.
On March 22, the Corps of Discovery began the long journey back to St. Louis. Lewis decided not to send any of the men back with a copy of his notes by sea, as was usually customary, because of the small number of people in the group. Instead, Lewis decided that the group would travel two different routes, in order to see as much of the territory as possible on the way back to St. Louis.
As a parting gift, Lewis gave Fort Clatsop to Coboway, the chief of the Clatsops. Lewis and Clark had no use for the fort, as they were returning east with no plans to revisit the fort in the near future. Because of the heavy rainfall of the region, the original Fort Clatsop rotted away by the middle of the 19th century.
The Clatsops used the fort as a useful base for security and other purposes, though they did strip away part of the wood for other uses.  The area soon became a very important site for the fur trade in the Pacific Northwest. The location of the fort near the Pacific Ocean and the Columbia River made it a natural site for the fur trade, which expanded rapidly in the years after Lewis and Clark left. Numerous fur trading companies, including the American Fur Company and the Hudson's Bay Company, constructed headquarters in the region. The region quickly became a very important part of the fur trade.
Since then, there have been two reconstruction efforts. The first, in 1955, lasted for 50 years until a fire destroyed the entire structure in the late evening of October 3, 2005. Federal, state, and community officials immediately pledged to rebuild it. A 9-1-1 operator's insistence that the fire was no more than fog over the nearby Lewis and Clark River delayed firefighters’ arrival by about 15 minutes, possibly impacting their ability to save part of the structure. Investigators found no evidence of arson. The fire started in one of the enlisted men's quarters, where earlier in the day there had been an open hearth fire burning. It took 18 months to build the 1955 reconstruction, much longer than the 3.5 weeks it took to build the original. Shortly after the fire, a second replica was built and finished in 2006. In spite of the loss, the fire renewed archaeological interest in the site, as excavations had not been possible while the replica was standing. Additionally, the new replica was built utilizing information on the original fort that was not available for the 1955 replica. The 2006 replica also features a fire detection system.
The replica of the fort isn't in the exact location of the original, as no remains of the original fort have been found. However, it is thought to be quite close to the exact location.
June 28–29: First trial in new territory. Pvt. John Collins is on guard duty and breaks into the supplies and gets drunk. Collins invites Pvt. Hugh Hall to drink also. Collins receives 100 lashes, Hall receives 50 lashes.
July 11–12: Second trial in new territory. Pvt. Alexander Hamilton Willard is on guard duty. Is charged with lying down and sleeping at his post whilst a sentinel. Punishable by death. He receives 100 lashes for four straight days.
August 3: The Corps of Discovery holds the first official council between representatives of the United States and the Oto and Missouri Indians at Council Bluffs, Iowa. They hand out peace medals, 15-star flags and other gifts, parade men and show off technology.
August 4: Moses Reed said he was returning to a previous camp to retrieve a knife but he was actually returning to St. Louis (deserting).
August 18: George Drouillard returns to camp with Reed and Otos' Chief Little Thief. Reed is sentenced to run the gauntlet (approximately 500 lashes) and is discharged from the permanent party.
August 18: Captain Meriwether Lewis's 30th birthday.
August 20: Sergeant Charles Floyd dies. He dies from bilious chorlick (ruptured appendix). He is the only member lost during the expedition.
September 7: The expedition drives a prairie dog out of its den (by pouring water into it) to send back to Jefferson.
September 14: Hunters kill and describe prairie goat (antelope).
September 25–29: A band of Lakota Sioux demand one of the boats as a toll for moving further upriver. Meet with Teton Sioux. Close order drill, air gun demo, gifts of medals, military coat, hats, tobacco. Hard to communicate language problems. Invite chiefs on board keelboat, give each 1⁄2 glass whiskey, acted drunk wanted more. Two armed confrontations with Sioux. Some of the chiefs sleep on boat, move up river to another village, meet in lodge, hold scalp dance.
October 8–11: Pass Grand River home of the Arikara Indians 2,000+. Joseph Gravelins trader, lived with Arikara for 13 yrs. Pierre Antoine Tabeau lived in another village was from Quebec.
October 13: Pvt. John Newman tried for insubordination (who was prompted by Reed) and received 75 lashes. Newman was discarded from the permanent party.
October 24: Met their first Mandan Chief, Big White. Joseph Gravelins acted as interpreter.
October 24: Expedition reaches the earth-log villages of the Mandans and the Hidatsas. The captains decide to build Fort Mandan across the river from the main village.
October 26: Rene Jessaume lived with Mandan for more than 10 years, hired as Mandan interpreter. Hugh McCracken a trader with the North West Company. Francois-Antoine Larocque, Charles MacKenzie also visited L&C.
November–December: Constructed Fort Mandan.
November 2: Hired Baptiste La Page to replace Newman.
December 24: Fort Mandan is considered complete. Expedition moves in for the winter.
January 1: The Corps of Discovery celebrates the New Year by "Two discharges of cannon and Musick—a fiddle, tambereen and a sounden horn."
February 9: Thomas Howard scaled the fort wall and an Indian followed his example. "Setting a pernicious example to the savages" 50 lashes—only trial at Fort Mandan and last on expedition. Lashes remitted by Lewis.
February 11: Sacagawea gives birth to Jean Baptiste Charbonneau, the youngest member of the expedition. Jean Baptiste is nicknamed "Pompy" by Clark. Lewis aided in the delivery of Sacagawea's baby, used rattle of rattlesnake to aid delivery (Jessaume's idea).
April 7–25: Fort Mandan to Yellowstone River.
April 7: The permanent party of the Corps of Discovery leaves Fort Mandan. The keelboat is sent down river. Left Fort Mandan in six canoes and two pirogues. Thomas Howard received a letter from his wife Natalia.
April 25: Reached Yellowstone River Roche Jaune—sent Joseph Field up river to find Yellowstone. He saw Big Horn Sheep and brought back horns. Lewis searched area thought it would be a good area for fort. Future forts were built, Fort Union and Fort Buford.
May 14: A sudden storm tips a pirogue (boat) and many items, such as supplies and the Corps' journals, spill over into the river. Sacagawea calmly recovers most of the items; Clark later credits her with quick thinking.
May 8: Milk river. Called because of its milky white appearance. Natives called it "a river which scolds all others".
June 3–20: Marias River to the Great Falls.
June 3: The mouth of the Marias River is reached. Camp Deposit is established. Cached blacksmith bellows and tools, bear skins, axes, auger, files, two kegs of parched corn, two kegs of pork, a keg of salt, chisels, tin cups, two rifles, beaver traps. Twenty-four lb of powder in lead kegs in separate caches. Hid red pirogue. Indians did not tell them of this river. Unable to immediately determine which river is the Missouri, a scouting party is sent to explore each branch, North fork (Marias), South fork (Missouri). Sgt. Gass and two others go up south fork. Sgt. Pryor and two others go up north fork. Can't decide which river is Missouri. Clark, Gass, Shannon, York and Fields brothers go up south fork. Lewis, Drouillard, Shields, Windsor Pryor, Cruzatte, Lepage go up north fork. Most men in expedition believe north fork is the Missouri. Lewis and Clark believe south fork is Missouri and followed that fork.
June 13: Scouting ahead of the expedition, Lewis and four companions sight the Great Falls of the Missouri River, confirming that they were heading in the right direction. Lewis writes when he discovers the Great Falls of the Missouri. "When my ears were saluted with the agreeable sound of a fall of water and advancing a little further I saw the spray arrise above the plain like a column of smoke.....began to make a roaring too tremendous to be mistaken for any cause short of the great falls of the Missouri."
June 14: Lewis takes off on an exploratory walk of the north side of the river. Lewis shoots a bison. While he is watching the bison die, a grizzly bear sneaks up on him and chases him into river.
June 21 – July 2: A portage of boats and equipment is made around the falls.
June 27: Cached: desk, books, specimens of plants and minerals, two kegs of pork, 1⁄2 keg of flour, two blunderbusses, 1⁄2 keg of fixed ammo, and other small articles.
June: 18.4 miles Clark surveyed route. Clark was the first white man to see falls from south side of river. As Clark was surveying route he discovered a giant fountain (Giant Springs).
June 22 – July 9: Construction of iron framed boat used to replace pirogues. It was floated on July 9 but leaked after a rain storm. The boat failed and was dismantled and cached July 10.
July 10–15: Established canoe camp to construct 2 new dugout canoes to replace failed iron frame boat.
August 13: Lewis meets Cameahwait, leader of a band of Shoshone
August 15–17: Lewis returns across Lemhi Pass with Cameahwait and sets up Camp Fortunate.
August 17: A council meets with the Shoshone, during which Sacagawea learns the fate of her family and reveals that Cameahwait is her brother. Lewis and Clark successfully negotiate for horses for passage over the Rocky Mountains. They buy 29 horses for packing or eating with uniforms, rifles, powder, balls, and a pistol. They also hire Shoshone guide Old Toby.
August 18: Captain Lewis's 31st birthday. In his journal, he scolds himself for being "indolent", or lazy, and vows to spend the rest of his life helping people.
August 26: Lewis and the main party cross the Continental Divide at Lemhi Pass. They thereby leave the newly purchased United States territory into disputed Oregon Country.
November 24: The Corps takes the matter of where to spend the winter to a vote. York, a slave, and Sacagawea, a woman, were allowed to vote. It was decided to camp on the south side of the Columbia River.
December 7 – March 23, 1806: Fort Clatsop sewed 338 pairs of moccasins.
December 25: Fort Clatsop, the Corps' winter residence, is completed.
January 1: Discharged a volley of small arms to usher in the new year. Several Corps members build a salt-making cairn near present-day Seaside, Oregon.
March 22: Corps of Discovery leave Fort Clatsop for the return voyage east.
July 13: Reached White Bear Island. Opened cache and many items were ruined. The iron frame of the boat had not suffered materially.
July 15: Lewis explores Maria's river separates from Gass to meet at Mouth of Maria's between Aug. 5 and no later than Sept 1. Maria's River expedition includes M. Lewis, R. Fields, J. Fields, G. Drouillard.
July 15–26: Camp Disappointment. Marias River does not go far enough north. Indians finally discovered.
July 20: Sgt. Ordway's party (from Clark's party) meets Sgt. Gass's party at the Great Falls of the Missouri.
July 27: The Blackfeet Indians try to steal Lewis's group's rifles. A fight broke out and two Indians were killed. This is the only hostile encounter with an Indian tribe.
July 28: Lewis meets Ordway and Gass.
July 3: Clark explores Yellowstone—leaves for Three Forks and Yellowstone. Sgt. Pryor, G. Gibson, H. Hall, R. Windsor. Sgt. Ordway, J. Colter, J. Colter, P. Cruzatte, F. LaBiche, T. Howard, J. Shields, B. LaPage, G. Shannon, J. Potts, W. Brattan, P. Wiser, P. Willard, J. Whitehouse, T. Charboneau, Sacagawea & Pomp, York.
July 6: Clark's group crosses the Continental Divide at Gibbons Pass.
July 8: Reached Camp Fortunate dug up cache from year before—tobacco most prized.
July 13: Sgt. Ordway splits from Clark to travel up Missouri River to meet Lewis and Gass.
August 3: Clark arrives at confluence of Missouri and Yellowstone Rivers—moves down river because of mosquitoes.
August 8: Pryor and party reached Clark. Pryor and party (Sgt. Pryor, G. Gibson, H. Hall, R. Windsor) left Clark with horses and a letter to Hugh Henry to get Sioux to go to Washington and make peace with other Indians. Horses stolen, had to make bull boats to get across and down river.
August 11: Lewis is accidentally shot by a member of his own party.
August 12: The two groups rejoin on the Missouri River in present-day North Dakota.
August 18: Capt. Lewis's 32nd birthday.
August 14: Reached Mandan Village. Charbonneau and Sacagawea stayed. John Colter went back up river with trappers Hancock and Dickson provided rest of company stay with expedition all the way to St. Louis.
September 23: The Corps arrives in St. Louis, ending their journey after two years, four months, and ten days.