5th Grade US Geography Questions That Many Americans Can't Answer Correctly

We often assume that basic U.S. geography is common knowledge, with certain facts expected to be known by every citizen. For instance, it's widely believed that everyone knows the United States consists of 50 states, with 48 of them being contiguous, and that Alaska and Hawaii are the exceptions. Or that Rhode Island is the smallest state, and the Colorado River flows through the Grand Canyon. But it turns out, not everyone is aware of these facts.

Many of the questions that we think are basic U.S. geography that everyone knows, most Americans get wrong, even the number of states that make up the nation. And there are probably many more that people don't know about U.S. geography. Take this quiz to see how you fare against the rest of the population.

This post was updated in March 2026 to include updated information about US geography facts.

Question

What is the largest freshwater lake not only in the U.S. but in the world by surface area?

Answer: Lake Superior

Lake Superior covers approximately 31,700 square miles, making it the largest freshwater lake in the world by surface area (but not by volume, which is Lake Baikal in Russia).

Question

What is the only state in the U.S. that shares its border with only one other state?

Answer: Maine

The only state that Maine shares a border with is New Hampshire.

Question

Why is the Great Salt Lake in Utah salty?

Answer: No Outlet

Utah's Great Salt Lake is salty because there are no outlets. Its tributaries deliver small amounts of salt, and once that water reaches the lake, it evaporates, leaving the salt behind.

Question

Which river flows through more states than any other U.S. river, and how many states does it flow through?

Answer: The Mississippi River

The Mississippi River flows through 10 states — Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana — which is tied with the Missouri River for the most states traversed by a U.S. river.

Question

What is the most densely populated state in the nation?

Answer: New Jersey

New Jersey covers 8,723 square miles and has a population of about 9.3 million people. That makes it the most densely populated state in the nation, with 1,257.7 people per square mile.

Question

What is the Mason-Dixon Line?

Answer: A Land Dispute Resolution

While many Americans simplify the purpose of the Mason-Dixon Line as separating the North from the South, its original purpose was to resolve a border dispute between the British colonies of Pennsylvania and Maryland. It is named after the land surveyors Charles Mason and Jeremiah Dixon. In pre-Civil War times, it was the line dividing the slave states of the South and the "free-soil" states of the North.

Question

How long is the Appalachian Trail, and where does it start and end?

Answer

The Appalachian Trail is approximately 2,197.9 miles long as of 2026. It stretches from Katahdin, Maine, to Springer Mountain, Georgia. FUN FACT: The fastest known time for completing the thru-hike of the Appalachian Trail is 40 days, 18 hours, and 5 minutes, set by Christian "Buddy Backpacker" Thomas. The average hiker takes 5-7 months to complete the journey.

Question

Where is the longest coastline in the United States?

Answer: Alaska

Alaska holds the title of the longest U.S. coastline, with a coastline of 6,640 miles. Including all tidal shoreline, Alaska's coastline is 33,904 miles.