In December of 1804, in the area around present-day Washburn, North Dakota, the temperature averaged 4 degrees above zero. The following month, January of 1805, the thermometer plunged further south, reaching 3.4 degrees below zero. But all was snug, or as snug as possible, at Fort Mandan, located on the north bank of the Missouri River, some seven miles below the mouth of the Knife River and directly opposite the lower Mandan Indian village.
The site for this winter haven in the wilderness had been selected during the fall of 1804 by Captain Meriwether Lewis and his co-leader Captain William Clark of the newly formed Corps of Discovery. Work on the fort began on November 3, 1804. Soon after, Private Joseph Whitehouse, a member of the corps, would record in his journal that all of the men were spending their time "diligently in the building of their huts and had made them convertible."
Clark chose this site for Fort Mandan in an area just south of the Indians' village and across the river from where most of the Mandans lived. He called the fort site a "hansom plain." The area was on a low point of ground and was covered with tall and heavy cottonwood trees.
The fort consisted of two rows of huts, set at an angle. There was a palisade on the riverside. There was, of course, a gate and a sentry post. The swivel gun, brought up from their boat, was mounted on the fort. The outside walls of the fort stood eighteen feet high. After a visit by the North West Company trader Francois-Antoine Larocuque, the man mentioned that the fort was built so strong that it was nearly "cannon-ball proof."
Larocuque's writing also tell us that Fort Mandan was built in a triangular shape, the two rows of houses making up two sides of the fort. These two rows of houses were not attached to each other, but were connected by a section of fortification that formed a demi-circle. This arrangement allowed the fort to be defended from two sides.
The building of the fort greatly interested the Indians in the area. From the beginning of construction the Mandans made daily crossings of the river just to stand and watch, and also to trade with the soldiers. The fort drew the attention, also, of more than the Mandans and trader Larocuque. On November 4, Clark recorded in his journal the arrival of yet another Frenchman, along with his two Indian wives. It was an event that, unknown to all involved at the time, would create stories that would be repeatedly recorded and told for the next two hundred years and beyond.
