3rd Grade Social Studies
The Topography of America
Unit 4
What is Topography?
Topography is the arrangement of the natural and artificial physical features of an area. Another word for "topography" is "landscape".
To the right is a Topographical map. As you can see, the rougher looking areas are where there are mountains. The green is where there are many forest and tree-filled areas. The middle looks slightly smoother than the rest of the map because it is all flat.
Major Mountain Ranges of the United States
Appalachian Mountain Range
The Appalachian Mountains, often called the Appalachians, are a system of mountains in eastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They once reached elevations similar to those of the Alps and the Rocky Mountains before experiencing natural erosion.
Rockies Mountain Range
The Rocky Mountains stretch some 3,000 miles from British Columbia and Alberta in Canada through Idaho, Montana, Wyoming, Colorado, and down to New Mexico in the U.S.
Major Rivers of the United States
Ohio River
The Ohio River is a 981-mile long river in the United States. It is located in the Southern and Midwestern United States, flowing southwesterly from western Pennsylvania south of Lake Erie to its mouth on the Mississippi River at the southern tip of Illinois.
Rio Grande River
The Rio Grande is one of the principal rivers in the southwest United States and northern Mexico. The Rio Grande begins in south-central Colorado in the United States and flows to the Gulf of Mexico. After passing through the length of New Mexico along the way, it forms part of the Mexico–United States border.
Colorado River
The Colorado River is one of the principal rivers in the Southwestern United States and northern Mexico. The 1,450-mile-long river drains an expansive, arid watershed that encompasses parts of seven U.S. states and two Mexican states.
Mississippi River
The Mississippi River is the second-longest river and chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system.
Hudson River
The Hudson River is a 315-mile river that flows from north to south primarily through eastern New York in the United States. The river originates in the Adirondack Mountains of Upstate New York, flows southward through the Hudson Valley to the Upper New York Bay between New York City and Jersey City.
St. Lawrence River
The Saint Lawrence River flows in a roughly north-easterly direction, connecting the Great Lakes with the Atlantic Ocean and forming the primary drainage outflow of the Great Lakes Basin.