* 1723 – Mathurin Jacques Brisson, French naturalist ( d. 1806 )

* 1806 – Francis II, the last Holy Roman Emperor, abdicates ending the Holy Roman Empire.

* 1806 – Battle of Mišar during the Serbian Revolution begins.

* 1806 – Santiago de Liniers, 1st Count of Buenos Aires re-takes the city of Buenos Aires, Argentina after the first British invasion.

* 1724 – George Stubbs, English painter ( d. 1806 )

* Anton Alexander Graf von Auersperg ( 1806 – 1876 ) – Austrian poet who wrote under the pseudonym of Anastasius Grün.

The Lewis and Clark Expedition spent the winter of 1805 – 1806 at Fort Clatsop, a small log structure south and west of modern day Astoria.

* 1806 – Michael Haydn, Austrian composer ( b. 1737 )

* 1727 – Michel Adanson, French botanist ( d. 1806 )

* William Bernard Ullathorne ( 1806 – 89 )

Following his conquest of most of Western Europe, the first Napoleon made his elder brother Joseph ( 1768 – 1844 ) king first of Naples ( 1806 – 1808 ) and then of Spain ( 1808 – 1813 ), his third brother Louis ( 1778 – 1846 ) king of Holland ( 1806 – 1810 ) ( subsequently forcing his abdication after his failure to subordinate Dutch interests to those of France ) and his youngest brother Jérôme Bonaparte ( 1784 – 1860 ) king of Westphalia, the short-lived realm created from some of the states of northwestern Germany ( 1807 – 1813 ).

* The Red River Expedition ( 1806 ) and the Pike Expedition were also commissioned by Jefferson.

The Lewis and Clark Expedition ( 1804 ) traveled up the Missouri River ; the Red River Expedition ( 1806 ) explored the Red River basin ; the Pike Expedition ( 1806 ) also started up the Missouri, but turned south to explore the Arkansas River watershed.

* 1806 – Construction is authorized of the Great National Pike, better known as the Cumberland Road, becoming the first United States federal highway.

* 1806 – Pike expedition: Lieutenant Zebulon Pike sees a distant mountain peak while near the Colorado foothills of the Rocky Mountains ( it is later named Pikes Peak ).

Reports from expeditions in 1806 by Lieutenant Zebulon Pike and in 1819 by Major Stephen Long described the Great Plains as " unfit for human habitation " and as " The Great American Desert ".

In 1806 Lieutenant Zebulon Pike, Major G. C. Sibley, Major S. H. Long, amongt others, began visiting the Pawnee villages.

Its name is in honor of General Zebulon Pike, of New Jersey, an explorer who led an expedition to southern Colorado and discovered Pikes Peak in 1806.

In 1806, Zebulon Pike led the Pike expedition westward from St Louis, Missouri, of which part of their journey followed the Cottonwood River through Marion County near the current towns of Florence, Marion, Durham.

In 1806, Zebulon Pike led the Pike expedition westward from St Louis, Missouri, of which part of their journey followed the Cottonwood River through Lyon County.

In 1806, Zebulon Pike led the Pike expedition westward from St Louis, Missouri, of which part of their journey followed the Cottonwood River through Chase County.

In 1806, Zebulon Pike led the Pike expedition westward from St Louis, Missouri, of which part of their journey followed the Cottonwood River through Marion County near the current towns of Florence, Marion, Durham.

Main Street spread to the west with construction of the National Pike through the town in 1806 ; the telegraph lines from Frederick to Hagerstown were routed through Middletown in 1854 ; and in 1896, car 11 of the Frederick Middletown Railway made its first run to Middletown.

The Sauk leader Quashquame led a village of Sauk, Meskwaki, and Ioway near Rocheport along Moniteau Creek in the first decade of the 19th century ; this village was noted by Zebulon Pike in 1806.

An early reference to the river as the Smoky Hill was by American explorer Zebulon Pike during his 1806 expedition to visit the Pawnee.

In 1806, Lieutenant Zebulon Pike, under orders to ascertain the source of the Red River, ascended the Arkansas River, made his way downstream on what turned out to be the Rio Grande, and was sent home by the Spanish authorities.

As a United States Army captain in 1806 – 1807, he led the Pike Expedition to explore and document the southern portion of the Louisiana Purchase and to find the headwaters of the Red River, during which he recorded the discovery of what later was called Pikes Peak.

After Pike's first expedition, Pike was almost immediately ordered by Wilkinson to mount a second expedition in 1806 to explore and map the Red River, evaluate natural resources, and establish friendly relations with Native Americans.

After the general meeting in 1806, Thompson travelled to Rocky Mountain House and prepared for an expedition to follow the Columbia River to the Pacific.

The Lewis and Clark Expedition, also known as the Corps of Discovery Expedition ( 1804 – 1806 ), was the first transcontinental expedition to the Pacific coast undertaken by the United States.

In 1804 Jefferson appointed Meriwether Lewis and William Clark as leaders of the expedition ( 1804 – 1806 ), which explored the Louisiana Territory and beyond, producing a wealth of scientific and geographical knowledge, and ultimately contributing to the European-American settlement of the West.

During the Napoleonic Wars, a British military expedition landed in the Cape Colony and defeated the defending Dutch forces at the Battle of Blaauwberg ( 1806 ).

Lewis and Clark on their 1804 – 1806 expedition into the territory of the newly acquired Louisiana Purchase carried portable soup.

Clay's most notable client was Aaron Burr in 1806, after the US District Attorney Joseph Hamilton Daviess indicted him for planning an expedition into Spanish Territory west of the Mississippi River.

The Lewis and Clark Expedition stopped several times in the future state of Iowa on their 1805 – 1806 expedition to the west coast.

The county derives its name from the Merced River, or El Río de Nuestra Señora de la Merced ( River of Our Lady of Mercy ); named in 1806 by an expedition, headed by Gabriel Moraga, which came upon it at the end of a hot dusty ride.

Then, another important group of explorers visited the region in 1805 – 1806, but this group came from the east, which marked the first cross-continental expedition.

On 10 June 1806, Fox offered a resolution for total abolition to Parliament: " this House, conceiving the African slave trade to be contrary to the principles of justice, humanity, and sound policy, will, with all practicable expedition, proceed to take effectual measures for abolishing the said trade ..." The House of Commons voted 114 to 15 in favour and the Lords approved the motion on 25 June.

The first known meeting with European Americans came in 1806 with the Lewis and Clark expedition.

After studying in Leipzig and at the University of Göttingen he visited England in the summer of 1806, carrying a letter of introduction from the naturalist Johann Friedrich Blumenbach to Sir Joseph Banks, who, with the other members of the African Association, accepted his offer in 1809 to launch an expedition to discover the source of the River Niger.

Soon after his return in 1806, Pike was ordered to lead an exploratory expedition of the southwestern part of the Louisiana Territory to find the headwaters of the Arkansas and Red rivers.

* Sacagawea ( c. 1788 – December 20, 1812 ) – accompanied and assisted Meriwether Lewis and William Clark on the Lewis and Clark Expedition ( 1804 – 1806 ), the first American overland expedition to the Pacific coast and back.