United States Geography

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Gulf Coastline

The Gulf of Mexico coastline extends 2,625 km (1,631 mi), from the southern tip of Texas to the southern reaches of Florida. The Spanish and French were the first Europeans to colonize the area. The United States expanded into the region in the early 19th century after purchasing Florida from Spain and Louisiana from the French. In 1845 the United States annexed Texas, which had recently won its independence from Mexico. During the westward expansion of the 19th century, New Orleans, at the mouth of the Mississippi, grew to become the most important port city on the Gulf Coast.

The discovery of large oil fields in Texas in the 1930s and the subsequent development of industry, beginning in the 1940s, spurred the economy of the Gulf Coast. Approximately 20 percent of the U.S. petroleum output comes from an area known as the Gulf Coast Petroleum Province, on the coastal plain between New Orleans, and the mouth of the Río Grande in Texas. Pipelines carry crude oil from regional and inland oil fields to many port cities. The southeastern portion of the Gulf Coast has become a major supplier of natural gas. In addition, nearly 25,000 oil and gas wells have been dug offshore, on the shallow continental shelf along the coastline.

The Gulf Intracoastal Waterway connects 9 of the 15 largest ports in the United States. This water route, primarily designed to accommodate barge traffic carrying bulk goods, consists of lagoons and canals protected by barrier islands along the Gulf Coast.

Houston, Texas, has become the largest city on the coast, with an economy based largely on oil refining. Its port is one of the busiest in the United States. New Orleans remains a prominent port city, supporting transportation of goods up and down the Mississippi River.

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Pacific Coastline

Unlike other coastal regions in the coterminous United States, the 2,081-km (1,293-mi) Pacific Coast has very little flat land associated with it, except in southern California, which has a relatively smooth coastline. In other areas, the Coast Ranges plunge directly into the ocean in many places. In northern California, Oregon, and Washington, the coastline becomes increasingly irregular, consisting of a variety of bays, fjords, peninsulas, and islands.

The population along the Pacific coastline is concentrated in large urban centers. Los Angeles is the busiest port and largest city on the West Coast. Although the entire Pacific coastline is threatened by the dangers of earthquakes and violent Pacific storms, the population continues to grow. People from across the United States have flocked to the Pacific states, and immigrants from around the world, especially from Asia, have established homes in this area.

Many of the region’s coastal cities began as ports for shipping lumber or as processing locations for the fishing activities that are still important along the entire length of the coast. During the last half of the 20th century, as the focus of U.S. trade began shifting away from Europe toward Latin America and Asia, the importance of international business, shipping, and transportation functions grew in cities such as Los Angeles and San Francisco in California, and Seattle in Washington.

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Alaska Coastline

The coastline of Alaska, bordering the Pacific and Arctic oceans, is 10,690 km (6,640 mi) long. Much of Alaska’s southern coastline has large bays, inlets, and prominent fjords, which were created largely through glaciation. High mountains of the Alaska Range skirt this part of the coastline, often plunging directly into the Pacific Ocean. Hundreds of islands, including the Aleutians, are concentrated off the southern coastal area. The large Yukon River delta is a dominant feature of the western coastline. The tundra landscape of the northern coastline lies on the flat Arctic Coastal Plain adjacent to the Arctic Ocean.

Much of Alaska’s economy is based on profitable offshore fisheries and on 2.2 million hectares (5.5 million acres) of commercial forests. Both of these businesses are tied directly to the coastal areas, where warm Pacific winds keep most of Alaska’s coastline ice-free year round, allowing for continuous fishing and transportation for logging operations. The Trans-Alaska Pipeline connects the oil fields of the Arctic coastal area to the southern Alaska coastline, at Prince William Sound. Approximately 1.5 million barrels of oil are transported through this pipeline every day. Most of the urban settlements in Alaska are concentrated along the coastline, with the notable exception of Fairbanks, situated in the heart of Alaska along a tributary of the Yukon River.

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Hawaii Coastline

Hawaii has a coastline totaling 1,210 km (750 mi) in length. The scenic vistas and tropical beaches of Hawaii’s shores attract millions of tourists each year and have contributed greatly to the state’s economy. Because the islands are composed of fairly soft volcanic rock, which erodes quickly, the coastline is generally rocky. Areas of sheer cliffs, such as the rugged Na Pali coast on the island of Kauai, tower above the sea and beaches of white coral sand often lie tucked between the headlands. Several black sand beaches, worn from lava, dot the southeastern shore of the island of Hawaii, where the most recent lava flows meet the sea.

The scenic vistas and tropical beaches of Hawaii’s shores attract millions of tourists each year and have contributed greatly to the state’s economy. Although the coastline is extremely beautiful, it can also conceal hidden dangers. Large waves often break over the coral reefs that form just offshore of many beaches. These waves create perfect conditions for surfing, which originated in Hawaii and nearby Pacific islands, but it can also cause treacherous undertows that threaten swimmers. On rare occasions, offshore earthquakes trigger tsunamis, or giant sea waves, which can reach heights of about 9 m (about 30 ft). Tsunamis can cause extensive damage to low-lying coastal areas.

Hawaii is one of the world’s most isolated island chains. It is impossible for imports and exports to travel by land and expensive for them to arrive by air. Consequently, ships carry most of the commercial trade among the islands and between Hawaii and the mainland. Honolulu on Oahu is by far the leading port of the islands. Other important ports include Barbers Point on Oahu, Kahului on Maui, Hilo on Hawaii, and Nawiliwili Harbor on Kauai. Hawaii’s strategic mid-Pacific location also makes the island important to United States naval defense. Pearl Harbor naval base, a major military installation, is situated on Oahu.

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Environment and Society

When European settlers first arrived in what would become the United States, they found an environment rich in natural resources. Succeeding generations of Americans took full advantage of these resources. The United States became a major agricultural producer and later emerged as the world’s leading industrial nation.

As the U.S. economy developed, the nation’s natural environment changed dramatically. Farms and ranches replaced the vast forests of the North and Northeast and the wild grasses of the Great Plains. Wildlife was affected, too, as trapping, hunting, and the encroachment of human settlements reduced the populations of many indigenous animals. In the 20th century, industrial output rose sharply in the nation as urban centers expanded and the population exploded. Pollution increased correspondingly.

A movement to conserve America’s wilderness areas first gained momentum in the later half of the 19th century, and the government set aside selected areas as wilderness reserves. Little was done to address the issue of pollution, however, until the 1960s, when the deteriorating environment became a matter of intense public debate. As a result, the government took action to preserve wildlife, reduce pollution, and design policies that would lessen the impact of human activity on ecological systems. By the end of the 20th century, significant efforts at conservation and at wise management of the environment were under way. Yet at the same time a variety of complex environmental issues, many of them international in scope, still lay ahead.

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