United States编辑历史

The United States of America (USA) is a federal republic primarily located in North America, comprising 50 states, a federal district (Washington, D.C.), five major self-governing territories, and various possessions. It is the world's third-largest country by total area and the third-most populous. Bordered by Canada to the north and Mexico to the south, the nation spans diverse geographical regions, from Arctic tundra in Alaska to subtropical climates in Florida. Its history began with indigenous settlement, followed by European colonization, independence from Great Britain in 1776, westward expansion, and industrial growth. The United States is a global political and economic power, known for its cultural influence, innovation, and demographic diversity.

# 1 Geography

## 1.1 Physical Regions

### 1.1.1 Atlantic Coastal Plain
The Atlantic Coastal Plain stretches along the eastern seaboard from the Gulf of Mexico to the northeastern United States. It is characterized by flat, low-lying terrain, extensive wetlands, and barrier islands. Major cities such as New York, Philadelphia, and Washington, D.C., lie within this region.

### 1.1.2 Appalachian Mountains
The Appalachian Mountains run from Alabama to Maine, forming a series of ridges, valleys, and plateaus. Their elevation is moderate, with Mount Mitchell in North Carolina being the highest peak at 6,684 feet. The range is rich in coal deposits and historically served as a barrier to westward expansion.

### 1.1.3 Interior Plains
The Interior Plains cover a vast area of the central United States, extending from the Appalachians to the Rocky Mountains. This region includes the Great Plains, known for its flat grasslands and agricultural productivity, and the Central Lowlands. It is drained by the Mississippi River system.

### 1.1.4 Rocky Mountains
The Rocky Mountains are a major mountain system running from Alaska to New Mexico. With peaks exceeding 14,000 feet, they contain numerous national parks and are a sou