commanders at the fort. The United States conducted several negotiations with American Indians at Fort Crawford during the 1820s. One of the largest Indian councils in U.S. history was held at the fort in 1825, when over 5000 representatives of nearly a dozen Native American nations gathered to discuss and sign the first Treaty of Prairie du Chien. Because of the first Fort Crawford's location alongside the Mississippi River, diseases such as malaria and dysentery were common among the troops. They did not understand the role of mosquitoes and sanitation in these diseases. In addition, the fort's wooden walls rotted because of seasonal flooding that took place nearly every spring. The post took meteorological observations in 1822. In 1826, after a major flood, the garrison at Fort Crawford was ordered to leave Prairie du Chien and reinforce Fort Snelling in Minnesota. During 1827, while no troops remained in Prairie du Chien, a group of hostile Winnebago Indians led by chief Red Bird murdered a family of settlers near the abandoned fort. This incident was the start of the Winnebago War of 1827. The federal government ordered the return of soldiers to Prairie du Chien. Shortly afterward, the Army decided that the first Fort Crawford was no longer habitable. In 1828 a decision was made to build a new fort on higher ground. Maj. Stephen W. Kearny, commanding officer at the time, surveyed the area and chose a site for the new fort upon a hill near the Mississippi River's eastern bank. Second Fort Crawford The construction of the second Fort Crawford began in 1829 under the direction of the new commander, Col. Zachary Taylor, later elected as President of the United States. The new fort's location on the mainland in Prairie du Chien was much more floodproof. In addition, to make the fort more weather-proof, it was decided to construct the structure using quarried limestone rather than wood. Use of this material and delays in federal funding resulted in delays to complete the new fort; it was not finished until 1835. Troops in Prairie du Chien were unable to fully occupy the new fort's barracks until 1832, and in the meantime remained at the first Fort Crawford. Army surgeon Dr. William Beaumont did his best to keep the troops healthy. Beaumont would later achieve fame for a series of experiments on human digestion which he conducted at locations across the