7 of the Most Interesting State Borders in the U.S.

Since the nation’s founding, state borders have been decided for a number of reasons, whether those were natural features (such as rivers or mountain ranges), historic transportation routes, land purchases, or political factors. As a result, state borders don’t always criss-cross the country in neat lines. Discover seven of the most interesting state borders in the U.S. and how they came to exist.

Northwest Angle, Minnesota – Where You’ll Need a Passport to Visit

Minnesota’s Northwest Angle (which locals simply call “the Angle”) is the northernmost part of the contiguous United States and the only part of it that lies north of the 49th parallel. The area is a curious border oddity resulting from a mapmaker’s mistake. When the Treaty of Paris was codified in 1783 (ending the Revolutionary War), it marked the U.S.-Canada border at what was thought to be the source of the Mississippi River’s headwaters, but the line was actually drawn 150 miles north. This mistake left the Angle marooned in Canada, surrounded on three sides by Lake of the Woods and accessible only by road from Manitoba (you’ll need a passport) — or by boat or snowmobile across the lake. 

Missouri and Tennessee – The States That Border the Most Other States

Both Missouri and Tennessee share borders with eight other states. Missouri borders Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas, and Nebraska. For Tennessee, those states are Kentucky, Virginia, North Carolina, Georgia, Alabama, Mississippi, Arkansas, and Missouri. The Mississippi River divides Tennessee and Missouri — and also creates an enclave of part of Kentucky called the Kentucky Oxbow, which is surrounded by Missouri on three sides and Tennessee on the fourth side.

Nebraska – The Only Triply Landlocked State

To get to this Midwestern state from the nearest gulf, bay, or ocean, you’ll have to travel through three other states (or two states and a province of Canada), regardless of your origination point. All other landlocked states in the country are either singly or doubly landlocked. Nebraska is home to about 2 million people and is known for its sprawling plains and robust agriculture industry.

Alaska – The Most Water Borders of Any State

Alaska isn’t just the largest state in the country by land area, it also has the most coastline — 33,904 miles of it (including islands). That’s four times more than the next state on the list, Florida, which has 8,436 miles of coast. Alaska is also the only state that shares a border with three different seas. The Chukchi Sea and the Bering Sea separate Alaska and Russia, and the Beaufort Sea is along Alaska’s north border. The state’s southern border runs along the Pacific Ocean and the Gulf of Alaska.

Kansas City – A City Split Down the Middle by a State Border

Kansas City, Kansas, and Kansas City, Missouri, are two separately incorporated cities but are part of the same metropolitan area. Why are there two Kansas Cities? Kansas City, Missouri, was founded in 1889 — a combination of settlements named Westport (founded in 1830) and the City of Kansas (founded in 1853). It was named after the Kansas River. By the 1870s, the City of Kansas was popular and growing quickly. Officials across the Missouri River in Kansas (which became a state in 1861) saw that and wanted to capitalize on it, so they formed Kansas City, Kansas, in 1872. The two cities are now divided by the Kansas-Missouri state line.

Carter Lake – A City in Iowa That’s Surrounded by Nebraska

Carter Lake is the only Iowa city that’s located west of the Missouri River. It’s bordered on three sides by Nebraksa and on one side by the Missouri River. The irregular border is the result of a 1877 flood that changed the flow of the Missouri River, causing an oxbow (a horseshoe-shaped bend) in this spot. Iowa and Nebraska got into a heated battle about who should own the space. The Supreme Court ruled it part of Iowa in 1892. However, Carter Lake didn’t become its own town until 1930, after it seceded from Council Bluffs, Iowa.

Ellis Island – A Border Determined by the Surpreme Court

The watery border between New York and New Jersey cuts right through Ellis Island in New York Harbor — once the country’s largest immigration station, where over 12 million immigrants were processed from 1892 to 1924. The Main Building, where immigrants entered as they arrived in the United States, is located in New York. But the island itself has been significantly expanded since then by land reclamation, and it is now 27.5 acres. New Jersey argued that the expanded portion of the island fell within its existing jurisdiction, and the Supreme Court ruled in its favor in 1998.