Physical Features of the Land¶

Summary¶

This chapter explores the diverse landforms that shape the American landscape. Students will learn about mountains, valleys, plains, plateaus, deserts, and coastal features. The chapter covers major mountain ranges including the Rocky Mountains and Appalachian Mountains, as well as important geographical features like the Great Plains and various plateaus that define different regions of the United States.

Concepts Covered¶

This chapter covers the following 17 concepts from the learning graph:

Mountains
Plains
Plateaus
Valleys
Hills
Deserts
Coastal Areas
Islands
Peninsulas
Rocky Mountains
Appalachian Mountains
Sierra Nevada
Cascade Range
Great Plains
Colorado Plateau
Columbia Plateau
Central Valley

Prerequisites¶

This chapter builds on concepts from:

America's Amazing Landforms¶

The United States has some of the most diverse landforms in the world! From towering mountains to flat plains, from scorching deserts to beautiful coastlines, our country has it all. In this chapter, you'll explore the physical features that make America's landscape so incredible.

Mountains¶

Mountains are the tallest landforms on Earth. They rise high above the surrounding land and often have steep sides and pointed or rounded tops called peaks.

Key facts about mountains:

They are formed when Earth's crust pushes together
The highest peaks may be covered with snow year-round
Mountains can affect weather patterns—one side may be wet while the other is dry
Many rivers begin in mountain snowfields

The United States has several major mountain ranges:

Mountain Range	Location	Highest Peak
Rocky Mountains	Western US	Mt. Elbert (14,440 ft)
Appalachian Mountains	Eastern US	Mt. Mitchell (6,684 ft)
Sierra Nevada	California	Mt. Whitney (14,505 ft)
Cascade Range	Pacific Northwest	Mt. Rainier (14,411 ft)
Alaska Range	Alaska	Denali (20,310 ft)

Highest Mountain in North America

Denali in Alaska is the highest mountain in all of North America at 20,310 feet! It was formerly called Mt. McKinley.

Plains¶

Plains are large, flat or gently rolling areas of land. They are often covered with grasses or used for farming because the flat land makes it easy to grow crops.

Types of plains in the United States:

Coastal plains - Flat land along the ocean (Atlantic and Gulf coasts)
Interior plains - Flat land in the middle of the country
Great Plains - A huge grassland region in the central US

Plains are important because:

They have rich soil for farming
They're easy to travel across
Many large cities developed on plains
They support grassland animals like bison and prairie dogs

Plateaus¶

A plateau is a flat, raised area of land—like a giant table! Plateaus are higher than the land around them but have flat tops, unlike mountains.

Facts about plateaus:

They are sometimes called "tablelands"
They can be formed by volcanic activity or by layers of rock pushed up
Rivers often cut deep canyons through plateaus
They can be hot deserts or cool highlands

Famous US plateaus include:

Plateau	Location	Special Features
Colorado Plateau	AZ, UT, CO, NM	Home to the Grand Canyon
Columbia Plateau	WA, OR, ID	Formed by ancient lava flows
Ozark Plateau	MO, AR, OK	Rolling hills and caves
Edwards Plateau	Texas	"Texas Hill Country"

Valleys¶

A valley is low land between mountains or hills. Valleys are often formed by rivers cutting through rock over millions of years, or by glaciers (giant ice sheets) carving out the land.

Types of valleys:

River valleys - Shaped like a "V" because rivers cut downward
Glacial valleys - Shaped like a "U" because glaciers carved them wider
Rift valleys - Formed when Earth's crust pulls apart

Famous valleys in the United States:

Central Valley in California - One of the world's most productive farming regions
Death Valley in California - The lowest and hottest place in North America
Shenandoah Valley in Virginia - A beautiful valley in the Appalachian Mountains

Many cities are built in valleys because:

Rivers provide water
The land is flat and easy to build on
Mountains provide protection from harsh weather

Hills¶

Hills are raised areas of land that are smaller and rounder than mountains. There's no exact rule for when a hill becomes a mountain, but hills are generally under 1,000-2,000 feet tall.

Characteristics of hills:

Lower and more rounded than mountains
Usually covered with grass, trees, or farms
Easier to climb than mountains
Found throughout the United States

Hilly regions of the US include:

The Ozark Hills in Missouri and Arkansas
The Black Hills of South Dakota
The rolling hills of New England
The Piedmont region between the Appalachians and the coast

Diagram: Landform Comparison¶

Landform Comparison Interactive Diagram

Type: microsim

Learning Objective: Students will compare (L4) different landforms and identify (L1) their key characteristics.

Bloom Level: Analyze Bloom Verbs: compare, identify, distinguish

Visual Elements: - Cross-section view showing mountains, hills, plateau, valley, and plains side by side - Labels for each landform with elevation markers - Color coding: browns for higher elevations, greens for lower - Simple trees and grass to show vegetation differences - River flowing through valley

Interactive Controls: - Hover over each landform to see name and description - Click for popup with fun facts - Toggle button to show/hide elevation markers - Quiz mode: "Which landform is flat on top?"

Canvas Layout: - Width: responsive - Height: 450px - Panoramic cross-section view

Behavior: - Hovering highlights the landform and shows info panel - Clicking shows detailed information in sidebar - Quiz mode tests identification skills

Instructional Rationale: A side-by-side comparison helps students see relative sizes and shapes of different landforms, making abstract definitions concrete.

Implementation: p5.js with layered terrain graphics

Deserts¶

A desert is an area that receives very little precipitation—usually less than 10 inches per year. Deserts can be hot or cold, but they are always dry!

US deserts include:

Desert	Location	Features
Mojave Desert	CA, NV, UT, AZ	Death Valley, Joshua trees
Sonoran Desert	AZ, CA, Mexico	Saguaro cacti, hot summers
Chihuahuan Desert	NM, TX, Mexico	Largest North American desert
Great Basin Desert	NV, UT, OR, ID	Cold desert, sagebrush

Desert adaptations:

Plants have thick stems to store water (like cacti)
Animals are often nocturnal (active at night when it's cooler)
Some areas have no plants at all (like sand dunes)

Not All Deserts Are Hot

The Great Basin Desert in Nevada and Utah is a cold desert—it gets snow in winter! Antarctica is also considered a desert because it gets very little precipitation.

Coastal Areas¶

Coastal areas are places where the land meets the ocean. The United States has thousands of miles of coastline along the Atlantic Ocean, Pacific Ocean, and Gulf of Mexico.

Types of coastal features:

Beaches - Sandy or rocky shores
Cliffs - Steep rock faces along the coast
Bays - Bodies of water partly surrounded by land
Harbors - Protected areas for ships
Wetlands - Marshy areas where land meets water

The US coastline includes:

Coast	States	Features
Atlantic Coast	Maine to Florida	Beaches, bays, barrier islands
Gulf Coast	Florida to Texas	Wetlands, bayous, barrier islands
Pacific Coast	California to Washington	Cliffs, beaches, sea stacks
Alaska Coast	Alaska	Fjords, glaciers, islands

Coastal areas are important for:

Fishing and shipping
Tourism and recreation
Wildlife habitats
Major port cities

Islands¶

An island is land completely surrounded by water. The United States has thousands of islands, ranging from tiny rocks to huge landmasses.

Types of US islands:

Continental islands - Close to the mainland (like Long Island)
Volcanic islands - Formed by underwater volcanoes (like Hawaii)
Barrier islands - Sandy islands protecting the coast (like the Outer Banks)
Coral islands - Built from coral reefs (like the Florida Keys)

Famous US islands:

Hawaii - A state made entirely of volcanic islands
Long Island - Off the coast of New York City
Puerto Rico - A US territory in the Caribbean
Kodiak Island - A large island in Alaska

Peninsulas¶

A peninsula is land surrounded by water on three sides but connected to the mainland on one side. The word comes from Latin: "paene" (almost) + "insula" (island).

Major US peninsulas:

Peninsula	Location	Features
Florida	Southeast US	Surrounded by Atlantic and Gulf of Mexico
Delmarva	MD, DE, VA	Between Chesapeake Bay and Atlantic
Upper Peninsula	Michigan	Between Lakes Superior, Michigan, and Huron
Olympic Peninsula	Washington	Rainforests and mountains
Baja California	Mexico (near US)	Desert peninsula

Think About It

Florida is the most famous US peninsula. Can you find it on a map? Notice how water surrounds it on the east (Atlantic Ocean), west (Gulf of Mexico), and south!

The Rocky Mountains¶

The Rocky Mountains (often called "the Rockies") are the largest mountain system in North America. They stretch over 3,000 miles from New Mexico all the way to Canada and Alaska!

Rocky Mountain facts:

They formed about 80-55 million years ago
They pass through 6 US states: NM, CO, WY, MT, ID, UT
The Continental Divide runs along the Rockies (rivers on one side flow to the Pacific, rivers on the other side flow to the Atlantic/Gulf)
Many ski resorts are located in the Rockies

Famous Rocky Mountain peaks:

Mt. Elbert, Colorado (14,440 ft) - Highest in the Rockies
Longs Peak, Colorado - In Rocky Mountain National Park
Grand Teton, Wyoming - A dramatically pointed peak

Wildlife in the Rockies includes elk, bighorn sheep, mountain lions, and grizzly bears!

Diagram: Rocky Mountains 3D View¶

Rocky Mountains Interactive Map

Type: microsim

Learning Objective: Students will locate (L1) the Rocky Mountains and identify (L1) states they pass through.

Bloom Level: Remember Bloom Verbs: locate, identify, name

Visual Elements: - Map of western United States with Rocky Mountains highlighted - Mountain range shown in brown/white colors indicating elevation - State boundaries and labels - Major peaks marked with triangles - Continental Divide line shown

Interactive Controls: - Hover over states to highlight Rocky Mountain portions - Click peaks to see name, height, and photo - Toggle to show/hide Continental Divide - "Trace the Range" mode to follow the mountains from Mexico to Canada

Canvas Layout: - Width: responsive - Height: 430px - Map with info panel on side

Behavior: - Highlighting shows which states the Rockies pass through - Clicking peaks shows information cards - Continental Divide explains water flow east vs west

Instructional Rationale: An interactive map helps students understand the immense scale of the Rocky Mountains and how they affect the entire western United States.

Implementation: p5.js with elevation shading and state boundaries

The Appalachian Mountains¶

The Appalachian Mountains are the major mountain range of eastern North America. They are much older and more worn down than the Rockies.

Appalachian Mountain facts:

They formed about 480 million years ago (very ancient!)
They stretch from Alabama to Maine and into Canada
They are lower and more rounded than the Rockies (erosion over time)
The Appalachian Trail runs 2,190 miles along the range

Sub-ranges of the Appalachians:

Sub-range	Location	Features
Great Smoky Mountains	TN, NC	Most visited national park
Blue Ridge Mountains	VA, NC, GA	Beautiful blue haze
White Mountains	NH, ME	Mt. Washington (severe weather)
Green Mountains	Vermont	Covered with forests
Allegheny Mountains	PA, WV, VA	Coal mining region

The Appalachians were once as tall as the Rockies, but hundreds of millions of years of erosion wore them down to their current height.

The Sierra Nevada¶

The Sierra Nevada ("Snowy Range" in Spanish) is a mountain range in eastern California. It contains the highest peak in the lower 48 states!

Sierra Nevada facts:

Mt. Whitney (14,505 ft) is the highest peak in the lower 48 states
Yosemite National Park is located here (famous for waterfalls and granite cliffs)
Lake Tahoe sits between the Sierra Nevada and the Carson Range
Heavy snowfall provides water for California farms and cities

Famous Sierra Nevada features:

Half Dome and El Capitan in Yosemite
Sequoia groves with the world's largest trees
Lake Tahoe - one of the largest and deepest lakes in the US
Numerous ski resorts

The Cascade Range¶

The Cascade Range runs from northern California through Oregon and Washington into Canada. It is famous for its volcanic peaks!

Cascade Range facts:

Many peaks are dormant (sleeping) volcanoes
Mt. St. Helens erupted in 1980, causing massive destruction
The range creates a "rain shadow" - wet on the west, dry on the east
Dense forests of evergreen trees cover the western slopes

Major Cascade peaks:

Peak	State	Height	Volcanic?
Mt. Rainier	WA	14,411 ft	Yes (dormant)
Mt. Shasta	CA	14,179 ft	Yes (dormant)
Mt. Hood	OR	11,250 ft	Yes (dormant)
Mt. St. Helens	WA	8,363 ft	Yes (active!)

The Great Plains¶

The Great Plains are a vast, flat region in the center of North America. They stretch from Texas to Canada and from the Rocky Mountains to the Mississippi River.

Great Plains characteristics:

Mostly flat or gently rolling grassland
Very few trees (too dry for forests)
Rich soil perfect for farming wheat and corn
Home to bison, pronghorn, and prairie dogs

The Great Plains include parts of these states:

Texas, Oklahoma, Kansas, Nebraska
South Dakota, North Dakota
Colorado, Wyoming, Montana
New Mexico

The "Breadbasket" of America

The Great Plains grow so much wheat and grain that this region is called the "Breadbasket of America"—food from here feeds people around the world!

Diagram: Great Plains Cross-Section¶

Great Plains Interactive Explorer

Type: microsim

Learning Objective: Students will describe (L2) the Great Plains region and explain (L2) why it is important for agriculture.

Bloom Level: Understand Bloom Verbs: describe, explain, identify

Visual Elements: - Map of central US showing Great Plains extent - Cross-section from Rocky Mountains to Mississippi River - Icons for wheat, corn, cattle, oil wells - Climate indicators (rainfall amounts) - Cities marked for reference

Interactive Controls: - Hover to see state names and Great Plains coverage - Click regions to see what is produced there - Toggle between "Physical Features" and "Agriculture" views - Animation showing how flat the land is compared to mountains

Canvas Layout: - Width: responsive - Height: 400px - Split view: map above, cross-section below

Behavior: - Hovering shows state-specific information - Clicking shows agricultural products and facts - Cross-section clearly shows the flat terrain

Instructional Rationale: Understanding the Great Plains geography helps explain why this region became America's agricultural heartland.

Implementation: p5.js with map overlay and cross-section graphics

The Colorado Plateau¶

The Colorado Plateau is a high desert region covering parts of Utah, Arizona, Colorado, and New Mexico. It is famous for its red rock formations and canyons.

Colorado Plateau features:

Average elevation of 5,000-6,000 feet
The Colorado River carved the Grand Canyon through it
Red, orange, and pink rock formations
Many national parks and monuments

Famous places on the Colorado Plateau:

Location	State	Famous For
Grand Canyon	Arizona	Mile-deep canyon
Monument Valley	AZ/UT	Iconic rock formations
Arches National Park	Utah	Natural stone arches
Bryce Canyon	Utah	Colorful rock spires (hoodoos)
Mesa Verde	Colorado	Ancient cliff dwellings

The plateau's colorful rocks were formed from sand, mud, and minerals deposited over hundreds of millions of years.

The Columbia Plateau¶

The Columbia Plateau covers parts of Washington, Oregon, and Idaho. Unlike most plateaus, it was formed by ancient lava flows!

Columbia Plateau facts:

Formed by massive volcanic eruptions 17-14 million years ago
Lava layers are thousands of feet thick in some places
The Columbia River flows through it
Dry climate with sagebrush and grassland

Features of the Columbia Plateau:

Channeled Scablands - carved by ancient floods
Palouse Hills - famous for wheat farming
Dry Falls - an ancient waterfall larger than Niagara (now dry)
Snake River Canyon - carved through the lava

The Central Valley¶

The Central Valley of California is one of the most productive agricultural regions in the world. It's a long, flat valley between the Sierra Nevada and the Coast Ranges.

Central Valley facts:

About 450 miles long and 40-60 miles wide
Produces about 25% of all US food
Very hot, dry summers; mild, wet winters
Irrigated with water from Sierra Nevada snowmelt

Crops grown in the Central Valley:

Almonds, walnuts, pistachios
Grapes (wine and table grapes)
Oranges, lemons, and other citrus
Tomatoes, lettuce, and vegetables
Cotton and rice

The Central Valley has two main parts:

Sacramento Valley in the north (named after the Sacramento River)
San Joaquin Valley in the south (named after the San Joaquin River)

Key Takeaways¶

Excellent work exploring America's physical features! Here's what you've learned:

Mountains are the tallest landforms with peaks and steep sides
Plains are large, flat areas often used for farming
Plateaus are flat-topped elevated areas like giant tables
Valleys are low areas between mountains or hills
Hills are rounded elevated areas smaller than mountains
Deserts receive less than 10 inches of precipitation per year
Coastal areas are where land meets the ocean
Islands are land surrounded by water on all sides
Peninsulas are land surrounded by water on three sides
The Rocky Mountains are the largest range in North America
The Appalachian Mountains are ancient, worn-down eastern mountains
The Sierra Nevada contains the highest peak in the lower 48 states
The Cascade Range has volcanic peaks including Mt. St. Helens
The Great Plains are America's flat, agricultural heartland
The Colorado Plateau features the Grand Canyon and red rocks
The Columbia Plateau was formed by ancient lava flows
The Central Valley produces 25% of America's food

Review Questions¶

What is the difference between a plateau and a plain?

A plateau is a flat area that is elevated (raised up) above the surrounding land—like a table. A plain is a flat area at a lower elevation. Plateaus have steep sides; plains are at ground level.

Which mountain range is older—the Rockies or the Appalachians?

The Appalachian Mountains are much older! They formed about 480 million years ago, while the Rockies formed about 80-55 million years ago. That's why the Appalachians are lower and more rounded—they've had more time to erode.

What is a peninsula?

A peninsula is land that is surrounded by water on three sides but connected to the mainland on one side. Florida is the most famous US peninsula.

Why are the Great Plains called the 'Breadbasket of America'?

The Great Plains have rich soil and flat land perfect for growing wheat, corn, and other grains. This region produces so much food that it "feeds" America and much of the world!

Name two national parks located on the Colorado Plateau.

Grand Canyon National Park, Arches National Park, Bryce Canyon National Park, Capitol Reef National Park, Canyonlands National Park, Mesa Verde National Park (any two are correct!)