The Pacific Slope describes geographic regions in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

n, Central America

Central America

Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...

n, and South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

n countries that are west of the continental divide

Continental divide

A continental divide is a drainage divide on a continent such that the drainage basin on one side of the divide feeds into one ocean or sea, and the basin on the other side either feeds into a different ocean or sea, or else is endorheic, not connected to the open sea...

 and slope down to the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

. In North America, the Rocky Mountains

Rocky Mountains

The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 mark the eastern border of the Pacific Slope. In Central and South America, the region is much narrower, confined by the Sierra Madre Occidental

Sierra Madre Occidental

The Sierra Madre Occidental is a mountain range in western Mexico.-Setting:The range runs north to south, from just south of the Sonora–Arizona border southeast through eastern Sonora, western Chihuahua, Sinaloa, Durango, Zacatecas, Nayarit, Jalisco, Aguascalientes to Guanajuato, where it joins...

 in Central America, and by the Andes in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. The phrase is still used today mostly for scientific purposes to refer to regions inhabited by specific species.

It was and is still occasionally used to describe the region in North America during the 19th century and the expansion of the Old West

American Old West

The American Old West, or the Wild West, comprises the history, geography, people, lore, and cultural expression of life in the Western United States, most often referring to the latter half of the 19th century, between the American Civil War and the end of the century...

. It includes the states and territories west of the continental divide that runs down the Rocky Mountains

Rocky Mountains

The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...

 in North America. This included the territories and the states that emerged from them, including California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, Oregon Territory

Oregon Territory

The Territory of Oregon was an organized incorporated territory of the United States that existed from August 14, 1848, until February 14, 1859, when the southwestern portion of the territory was admitted to the Union as the State of Oregon. Originally claimed by several countries , the region was...

, Washington Territory

Washington Territory

The Territory of Washington was an organized incorporated territory of the United States that existed from February 8, 1853, until November 11, 1889, when the final extent of the territory was admitted to the Union as the State of Washington....

, Nevada Territory

Nevada Territory

The Territory of Nevada was an organized incorporated territory of the United States that existed from March 2, 1861, until October 31, 1864, when it was admitted to the Union as the State of Nevada....

, Idaho Territory

Idaho Territory

The Territory of Idaho was an organized incorporated territory of the United States that existed from March 4, 1863, until July 3, 1890, when the final extent of the territory was admitted to the Union as the State of Idaho.-1860s:...

, Colorado Territory

Colorado Territory

The Territory of Colorado was an organized incorporated territory of the United States that existed from February 28, 1861, until August 1, 1876, when it was admitted to the Union as the State of Colorado....

, and Utah Territory

Utah Territory

The Territory of Utah was an organized incorporated territory of the United States that existed from September 9, 1850, until January 4, 1896, when the final extent of the territory was admitted to the Union as the State of Utah....

. The region is drained by the Columbia

Columbia River

The Columbia River is the largest river in the Pacific Northwest region of North America. The river rises in the Rocky Mountains of British Columbia, Canada, flows northwest and then south into the U.S. state of Washington, then turns west to form most of the border between Washington and the state...

, Sacramento

Sacramento River

The Sacramento River is an important watercourse of Northern and Central California in the United States. The largest river in California, it rises on the eastern slopes of the Klamath Mountains, and after a journey south of over , empties into Suisun Bay, an arm of the San Francisco Bay, and...

, San Joaquin

San Joaquin River

The San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...

 and Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 systems. In the United States, the Pacific-slope Flycatcher

Pacific-slope Flycatcher

The Pacific-slope Flycatcher is a small insectivorous bird of the family Tyrannidae. It is native to coastal regions of western North America, including the Pacific Ocean and the southern Sea of Cortez, as far north as British Columbia and southern Alaska, but is replaced in the inland regions by...

 takes its name from the region it inhabits.

In Central America, it includes the mountain and coastal regions west of the Continental Divide in Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

 and southern Guatemala

Guatemala

Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...

, southwestern Honduras

Honduras

Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...

, western Nicaragua

Nicaragua

Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...

, and western/southwestern Costa Rica

Costa Rica

Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

, and southern Panama

Panama

Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...

. In Guatemala, the Pacific Slope region is a humid plain of fertile land divided into wide-spread plantation

Plantation

A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...

s (fincas) that grow abundant crops including sugarcane, bananas, and rubber. In Costa Rica

Costa Rica

Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

, the Pacific Slope refers to the region west of the continental divide at Monteverde, Costa Rica.

In South America, the Pacific Slope is the narrow region west of the highest points of the Andes, including western Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, central Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, western and southwestern Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, and eastern Chile

Chile

Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...

.