What's the Tallest Mountain in the US? (The Answer Depends on Your Tape Measure)

If you ask a third grader what the tallest mountain in the US is, they’ll probably yell "Denali!" and they’d be right. Sort of. It really depends on if you're standing on the beach or floating in a submarine.

Most people just want the quick answer: Denali in Alaska is the highest point in the United States, reaching a staggering 20,310 feet above sea level. It’s a beast. It’s so big it literally creates its own weather, and if you’re lucky enough to see it from Anchorage on a clear day, it looks like a white ghost looming over the city.

But here’s the thing. Geography is messy. Depending on how you define "tallest," you might actually be looking for a volcano in Hawaii or a granite wall in California.

What's the Tallest Mountain in the US from Sea Level?

Denali is the undisputed heavyweight champion of North America. For a long time, people called it Mount McKinley, but in 2015, the name was officially changed back to its indigenous Koyukon Athabascan name, which basically means "The Tall One."

The height is a bit of a moving target, too. Back in the 1950s, surveyors used older tech and pegged it at 20,320 feet. In 2015, the USGS used high-tech GPS and revised that down to 20,310 feet. It didn't actually shrink; we just got better at measuring the snow on top.

What makes Denali truly insane isn't just the elevation. It’s the "vertical rise." Most of the Himalayan giants, like Everest, sit on top of the Tibetan Plateau, which is already 14,000 feet high. Denali rises from a plain that’s only about 2,000 feet high. That means you’re looking at 18,000 feet of pure mountain staring you in the face.

Honestly, it’s arguably "taller" than Everest if you’re measuring from the base to the peak on land.

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The Secret Giant: Mauna Kea

If we’re being technical—and geologists love being technical—the tallest mountain in the US isn't in Alaska. It’s in Hawaii.

Mauna Kea is a dormant volcano on the Big Island. If you measure from sea level, it’s a respectable 13,803 feet. High, sure, but not record-breaking.

However, Mauna Kea starts at the bottom of the Pacific Ocean. If you drop a tape measure from the summit all the way to the very base on the sea floor, it measures over 33,500 feet.

That makes it taller than Mount Everest by more than 4,000 feet.

You’ve got a mountain that is mostly underwater, which is kinda wild to think about. When you stand at the visitor station near the summit to look at the stars (it has some of the best telescopes in the world), you’re actually standing on the tip of the largest mountain structure on Earth.

What About the "Lower 48"?

Alaska usually wins every geographic contest in the US, which can be annoying for hikers in the continental states. If you exclude Alaska and Hawaii, the title of the tallest mountain in the US belongs to Mount Whitney in California.

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Located in the Sierra Nevada, Mount Whitney hits 14,505 feet.

It’s a massive granite tooth that attracts thousands of hikers every year. The weirdest part? It’s only about 85 miles away from Badwater Basin in Death Valley, which is the lowest point in North America. You can literally see the highest peak in the contiguous US while standing 282 feet below sea level.

Getting to the top of Whitney is a "bucket list" item for a lot of people, but you can’t just show up. The Forest Service uses a lottery system because so many people want to hike it. If you don't win a permit, you aren't going up.

The Top 5 Highest Peaks in the US

Alaska basically hoards all the tall mountains. In fact, the top 10 highest peaks in the entire country are all in Alaska. If you're curious about the rankings (measured by height above sea level), here’s how the top tier looks:

1. Denali, Alaska: 20,310 feet. The king.
2. Mount Saint Elias, Alaska/Yukon: 18,008 feet. This one is crazy because it’s right on the coast. You can see the summit from a boat in the Gulf of Alaska.
3. Mount Foraker, Alaska: 17,400 feet. Denali’s "little" neighbor in the Alaska Range.
4. Mount Bona, Alaska: 16,550 feet. An ice-covered volcano.
5. Mount Blackburn, Alaska: 16,390 feet. The highest peak in the Wrangell Mountains.

It isn't until you get down to the 11th spot that California finally makes an appearance with Mount Whitney.

Why Does the Height Keep Changing?

You might see different numbers in different books. That’s because the Earth is alive. Tectonic plates are constantly shoving these mountains higher. Denali grows about one millimeter every year.

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But it’s also about technology. We used to use barometers and basic math. Now we use satellites and LiDAR. Even the "sea level" itself is tricky to define because the Earth isn't a perfect sphere; it’s more of a lumpy potato shape.

Planning Your Visit

If you want to actually see these giants, you have to plan differently for each:

• For Denali: Fly into Fairbanks or Anchorage. Take the park bus. You usually can't drive your own car deep into Denali National Park. Be prepared for the mountain to be "hidden" in clouds—it only shows its face about 30% of the time.
• For Mauna Kea: You can actually drive to the top of this one if you have a 4WD vehicle. Just watch out for altitude sickness. You’re going from sea level to nearly 14,000 feet in about two hours. Your lungs will notice.
• For Mount Whitney: Apply for the lottery in February. If you win, start training. It’s a 22-mile round trip if you do it in one day, and the air gets very thin at the top.

The tallest mountain in the US isn't just a number on a map. It’s a piece of the identity of the landscape. Whether it’s the icy walls of Denali or the volcanic roots of Mauna Kea, these places remind us how small we really are.

Next Steps for Your Adventure

If you’re serious about visiting the highest points in the US, your first move should be checking the National Park Service (NPS) websites for Denali or Sequoia (for Mount Whitney).

Check the "Current Conditions" pages specifically. In Alaska, snow can close roads in the middle of summer. In California, the Whitney Portal road often stays closed under deep snow until late May or June. If you're heading to Hawaii, make sure your rental car agreement actually allows you to drive up the Mauna Kea Access Road, as many standard contracts forbid it due to the steep grade and gravel sections.