December 3 1818:

Illinois achieves full statehood on this day.
Though Illinois presented unique challenges to immigrants unaccustomed to the soil and vegetation of the area,
it grew to become a bustling and densely populated state.

December 4 1867:

Former Minnesota farmer Oliver Hudson Kelley founds the Grange,
which became a powerful political force among western farmers.

Though he grew up in Boston, Kelley decided in his early twenties that he wanted to become a farmer.
In 1849, he booked passage on a steamboat for St. Paul, Minnesota.
Though the Minnesota area was dominated more by the Indian trade than farming,
Kelley shrewdly saw that the future of the region lay in agriculture,
and he proved to be a skilled and progressive farmer.
Kelley gained local fame for boldly experimenting with new crops, installing an elaborate irrigation system,
and buying one of the first mechanical reapers in the state.
His attempts at scientific farming and a series of columns he wrote for national newspapers brought him national recognition-in 1864,
he won a prestigious clerking position under the federal commissioner of agriculture in Washington, D.C.

1884 : Washington Monument completed

http://www.history.com/tdih.do?action=tdihVideoCategory&id=52285

On Dec 6:

1917 – A ship in Halifax Harbour carrying trinitrotoluene (TNT) and picric acid caught fire after a collision with another ship and exploded, devastating Halifax, Nova Scotia, Canada.

December 7 1805:

Having spied the Pacific Ocean for the first time a few weeks earlier,
Meriwether Lewis and William Clark cross to the south shore of the Columbia River (near modern-day Portland)
and begin building the small fort (Fort Clatsop) that would be their winter home.