Physical Geography of the United States Landforms At over 3.5 million square miles, the United States is the third-largest country in the world. Glacial activity and tectonic plate movement created the many landforms of the United States. The Pacific Ranges and the Rocky Mountains mark the western region, with some elevations over 20,000 feet. The flat landscape of the Great Plains lies in the center. Going east, the geologically older, but shorter Appalachian Mountains extend to the Piedmont’s fertile plateau, then the Atlantic Coastal Plain hems the shore.

Physical Geography of the United States Water Systems The many lakes, rivers, and tributaries helped encourage economic develop along their shores. The Mississippi River in the east and the Colorado River and Rio Grande in the west form two major waterways. The Continental Divide, a high ridge in the Rockies, determines the direction of river flow. Formed when glacier basins filled with water, the Great Lakes are part of the St. Lawrence Seaway System, a series of waterways that connect to the Atlantic Ocean.

Climate, Biomes, and Resources The large size of the United States leads to many variations in climate and vegetation. The oceans moderate temperature in coastal regions, while the interior experiences more extreme conditions. Rich in natural resources such as water, timber, fish, minerals, and fossil fuels, the United States helped speed industrialization and became one of the most prosperous countries in the world. Physical Geography of the United States

Human Geography of the United States History and Geography The physical environment played a significant role in the development of the United States. Native Americans, descendants of the first waves of migrations, occupied North America until the Europeans began immigrating in the 1500s. After gaining independence, the country nearly doubled in territory, gaining valuable land and resources. Industrialization and the great waves of immigrants who came to work in the United States made the population more mobile and urbanized.

Population Patterns More than 315 million people live in the United States. The aging of the population will cause challenges in government and health care costs. Population is increasing in Sunbelt states as manufacturing has declined in the North and Great Lakes region. Densely populated urban areas like the megalopolis between Boston and Washington, D.C. attract residents with economic opportunity. Human Geography of the United States

Society and Culture Today With its long history of immigration, the population of the United States is one of the most diverse countries in the world. This diverse population, coupled with the core value of religious freedom, contributed to the wide range of religions practiced today. The family remains important but the role of women is changing as more women seek employment and continue to outpace men in earning college degrees. Art and music, like jazz, developed by blending the influences of the country’s vast immigrant communities. Human Geography of the United States

Economic Activities The free market economy in the United States helped establish its great economic power. The economy has evolved from its agricultural origins to manufacturing to the postindustrial economy of today. Good transportation and reliable communications networks are critical pieces that enable the economy to function. The downturn beginning in 2008 caused by the subprime mortgage crisis is improving, but more growth is needed to return the United States to robust health. Human Geography of the United States

J OB -G ROWTH C HANGE, 2009–13

People and Their Environment: The United States Managing Resources Modern life poses a threat to the abundant natural resources in the United States. Conservation efforts by citizens and from all levels of government have increased to ensure resources will continue to flourish in the future. Resource management includes understanding and respecting the balances that exist in natural ecosystems. Efforts to reverse the damage have begun but more is needed to achieve sustainable levels.

Human Impact Acid rain and smog are consequences of human pollution of the air and water. Water pollution speeds eutrophication, which encourages the excessive algae growth that depletes water’s oxygen and suffocates fish. Projected water shortages could turn into droughts that cause billions of dollars in crop and livestock losses. People and Their Environment: The United States

Addressing the Issues The United States is continually improving its protection of the environment by using clean-air practices, searching for renewable sources of energy, and reducing waste. Federal legislation, such as the Clean Water Act and the Great Lakes Water Quality Agreement, has helped restore water quality throughout the country. The government is working to curb environmental damage by encouraging the use of renewable energy sources and offering incentives for companies to limit emissions. People and Their Environment: The United States