1. Montana
   Minnesota
2. New York
   Iowa

Niagara Falls is the common name for three waterfalls bordering New York (U.S.) and Ontario (Canada). The three falls are located on the Niagara River and, from smallest to largest, are the Horseshoe Falls, the American Falls and the Bridal Veil Falls.

1. Texas
   Hawaii
2. Washington
   Louisiana

Kilauea is an active shield volcano located on the island of Hawaii. It is the second youngest product of the Hawaiian hotspot and the most active of the five volcanoes that form the island of Hawaii (The Big Island).

1. Florida
   Arkansas
2. Arizona
   North Dakota

The Grand Canyon is a steep-sided canyon carved by the Colorado River. It measures 18 miles wide and 277 miles long. It is believed to have formed over 2 billion years ago, with the river cutting through the rock while the Colorado Plateau was uplifted.

1. Utah
   Wisconsin
2. Illinois
   Indiana

The Arches National Park, located in eastern Utah, is a park adjacent to the Colorado River. It is comprised of more 2,000 natural sandstone arches. Its most popular formation is the Delicate Arch, which measures approximately 60 feet.

1. Georgia
   Kentucky
2. Maine
   Vermont

The Mammoth Cave National Park is the longest cave system known in the world. It includes more than 400 miles of passageway. It is home to an endangered, sightless albino shrimp called the Kentucky cave shrimp.

1. Florida
   Minnesota
2. Montana
   Utah

The Monument Valley is a region of the Colorado Plateau located on the Arizona-Utah border. It is characterized by a series of large, sandstone buttes, the largest of the cluster measuring 1,000 feet from the bottom of the valley floor.

1. New Mexico
   Pennsylvania
2. Iowa
   Oklahoma

The Carlsbad Caverns is the primary attraction of the Carlsbad Caverns National Park situated in the Guadalupe Mountains of southeastern New Mexico. The cave is noted for its large number of calcite formations and a large limestone chamber named the "Big Room."

1. Wyoming
   Washington
2. Texas
   Louisiana

Old Faithful is a cone geyser situated in the Yellowstone National Park, Wyoming. It erupts at a regular interval of every 44 to 125 minutes, shooting 3,700 to 8,400 gallons of boiling water 106 to 185 feet in the air and lasts from 1 1⁄2 to 5 minutes.

1. North Dakota
   Utah
2. Tennessee
   Maryland

Bryce Canyon is the major feature of Bryce Canyon National Park. Despite its name, it is not a canyon, but a group of giant, geological structures called hoodoos, formed by the stream erosion and frost weathering of red, orange and white sedimentary rocks.

1. Wisconsin
   Illinois
2. Alaska
   Arkansas

Denali, also known as Mount McKinley, is the highest mountain peak in North America and the third most prominent and third most isolated peak on Earth. It is located in the Alaska Range and forms the centerpiece of the Denali National Park and Reserve.

1. Indiana
   Maine
2. South Carolina
   California

The Redwood National and State Parks is a complex of four parks that is home to one of the tallest and most massive tree species on Earth, the Coastal Redwood. On September 5, 1980, it was designated a World Heritage Site due to its rare ecosystem and cultural history.

1. Rhode Island
   California
2. Georgia
   Vermont

The Great Smoky Mountains are a subrange of the Appalachian Mountains and part of the Blue Ridge Physiographic Province. It is a UNESCO World Heritage Site and home to the largest population of black bears in the eastern U.S.

1. Minnesota
   Colorado
2. Washington
   Florida

Garden of the Gods is a public park which was designated a National Natural Landmark in 1971. Located in Colorado Springs, Colorado, it was created millions of years ago during a geological upheaval along a natural fault line.

1. Oklahoma
   Montana
2. Oregon
   Iowa

Crater Lake, situated in south-central Oregon, is a lake renowned for its deep blue color and water clarity. It is the deepest lake in the United States and is the result of a deep caldera formed by the collapse of the volcano, Mount Mazama.

1. Texas
   Wisconsin
2. North Dakota
   Maryland

Hamilton Pool is a natural pool that is the result of the collapsing of the dome of an underground river. It features a 50-foot waterfall which flows into a large, jade green pool surrounded by large slabs of limestone that rest near the water's edge.

1. California
   Texas
2. Louisiana
   Indiana

Death Valley, located near the border of California and Nevada, is a desert valley and one of the hottest places in the world at the height of summer. The valley's highest point is the Telescope Peak, while its lowest elevation is the Badwater Basin.

1. Illinois
   Tennessee
2. Arkansas
   Colorado

The Great Sand Dunes National Park and Preserve is a national park which contains the tallest dunes in North America, measuring up to 750 feet in height. The park encompasses 107,342 acres and is estimated to contain more than 5 billion cubic meters of sand.

1. New Jersey
   Pennsylvania
2. Alaska
   South Carolina

The Mendenhall Ice Caves are a series of caves and caverns encased in the 12-mile long Mendenhall Glacier located in Juneau, Alaska. This type of cave is the result of water flowing through a glacier and then creating a passageway through the ice.

1. Maine
   Florida
2. Alaska
   Oklahoma

The Hubbard Glacier, named after Gardiner Hubbard, is a glacier situated in eastern Alaska and part of Yukon, Canada. It measures 76 miles in length.

1. Georgia
   Minnesota
2. Nevada
   Montana

Valley of Fire State Park is a public recreation and nature preservation area that derives its name from red sandstone formations, the Aztec Sandstone. It has a warm and dry climate with daily summer highs ranging from 100°F to 115°F.

1. Wisconsin
   North Dakota
2. Washington
   Florida

Everglades National Park is a national park in Everglades, Florida, that attracts an average of 1 million visitors each year. It is the largest tropical wilderness and the third largest national park in the United States.

1. Vermont
   Iowa
2. Wyoming
   Rhode Island

The Yellowstone Caldera, also known as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano located in the northwest corner of Wyoming. The primary attractions of the caldera measure nearly 34 by 45 miles.

1. Arkansas
   Louisiana
2. Texas
   South Dakota

The Black Hills is a small and isolated mountain range which rises 7,244 feet from the Great Plains. It has diverse and plentiful wildlife, which include American bison, mountain lions, bighorn sheep, American flying squirrel and prairie dogs.

1. New Jersey
   Michigan
2. Maryland
   Pennsylvania

The Sleeping Bear Dunes is a National Lakeshore renowned for its natural features, including forests, dune formations, beaches, and ancient glacial formations. The park covers a total of 71,187 acres and is one of the most popular destinations for camping vacations.

1. Oregon
   Minnesota
2. Illinois
   Indiana

Hells Canyon is a 10-mile wide canyon which was carved by the waters of the Snake River that empties into the Pacific Ocean. The canyon measures 7,993 feet deep, making it the deepest river gorge in North America.

1. Maine
   Montana
2. Florida
   Oklahoma

Mount Desert Island is the largest island off the coast of Maine and the second-largest island on the eastern seaboard. The island is a popular vacation spot with an average 500,000 tourists visiting every year.

1. Tennessee
   Wisconsin
2. Arizona
   South Carolina

Antelope Canyon is a slot canyon formed by erosion of the Navajo sandstone due to flash flooding and sub-aerial processes. It is a source of tourism for the Navajo Nation and a popular attraction for sightseers and photographers.

1. Michigan
   Washington
2. North Dakota
   Georgia

Turnip Rock is a sea stack renowned for its unusual form which, as its name suggests, resembles that of a turnip. It is located in Lake Huron, Michigan, in shallow water a few meters offshore, close to a rock called Thumbnail.

1. Arkansas
   Iowa
2. Louisiana
   Oregon

Phantom Ship, located in Crater Lake, Oregon, is a natural rock formation formed from andesite rock. It derives its name due to its unique shape which resembles a ship, particularly in low-light conditions and foggy weather.

1. Pennsylvania
   Arizona
2. Texas
   Vermont

Horseshoe Bend is an incised meander of the Colorado River with a horseshoe shape situated near the town of Page, Arizona. It is located five miles downstream from the Glen Canyon dam and is accessible via hiking a 1.5-mile round trip from U.S. Route 89.

1. Minnesota
   Arizona
2. Montana
   Indiana

The Wave is a sandstone rock formation that is popular among photographers and hikers due to its colorful and undulating form and difficult hike to get there. It is located in the Coconino County of Arizona, near the northern border shared with Utah.

1. Illinois
   California
2. Oklahoma
   Florida

Devil's Postpile National Monument is an unusual rock formation of columnar basalt located near Mammoth Mountain in eastern California. The formation resembles tall posts stacked in a pile with an average diameter of 2 feet and a length of 60 feet.

1. New Jersey
   Maryland
2. Maine
   California

Skull Rock is a rock formation found in the Joshua Tree National Park in southeastern California. In addition to Skull Rock, other rock formations include Arch Rock, Bakers Dam, Ryan Mountain, and the Cholla Cactus Garden.

1. North Dakota
   Washington
2. Utah
   Wisconsin

Mesa Arch is a pothole arch situated in Canyonlands National Park, Moab, Utah. This natural arch was formed as a result of chemical weathering as water collected in natural depressions, eventually cutting through the layer below.

1. Maine
   California
2. Tennessee
   Vermont

The Tufa Towers are rare limestone rock formations located in the Mono Lake Tufa State National Reserve. These oddly-shaped rocks are found along the Mono Lake's shoreline, with a concentration of these towers at the south end of the lake.

1. Utah
   Iowa
2. Louisiana
   South Carolina

Devil's Garden is a region of the Arches National Park known for its series of arches and rock fins created due to erosion. The area includes several arches, such as the Tunnel Arch, Pine Tree Arch, Private Arch, Partition and the Dark Angel monolith.

1. Georgia
   Arkansas
2. Texas
   Kansas

Mushroom Rock State Park, situated in Smoky Hills, Kansas, is a state park renowned for its mushroom-shaped rock formations. These rocks are a type of hoodoos, which are the result of non-uniform erosion and weathering.

1. Florida
   Indiana
2. Montana
   Oklahoma

The Ouachita Mountains are a mountain range located in southeastern Oklahoma and western Arkansas. This region is home to several species of flora and fauna, including pine, hickory, oak, coyote, white-tailed deer, black bear and salamander.

1. Minnesota
   Hawaii
2. Illinois
   Oklahoma

Nakalele Point is a land mass in Maui, Hawaii, known for its blowhole, which produces strong geyser-like water spouts with tides and waves. The water ejected from the blowhole is capable of reaching a height of 100 feet in the air.

1. Wisconsin
   North Dakota
2. Nebraska
   Washington

Chimney Rock, located in Morrill County, western Nebraska, is a geological rock formation with a tall pillar which rises 4,228 feet above sea level. The pillar is made of Brule clay mixed with layers of Arikara sandstone and volcanic ash.