May 20, 2026
US State Borders Trivia: Which States Share the Most Neighbors?
Tennessee and Missouri both border 8 states — the most of any US state. Maine borders only one. The map of state adjacency is full of surprises, quirks, and geography trivia that stumps even the sharpest map enthusiasts. Test yourself below.
The Champions: 8 Neighbors Each
Tennessee borders Virginia, Kentucky, Missouri, Arkansas, Mississippi, Alabama, Georgia, and North Carolina. Its long, narrow east-west shape — about 440 miles wide but only 120 miles tall — gives it contact with states in three distinct regions: the Appalachian South, the Deep South, and the Mississippi Valley.
Missouri borders Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas, and Nebraska. Sitting at the geographic crossroads of the country, Missouri touches states in every direction and serves as the meeting point of the Great Plains, the Midwest, and the South.
Trivia Round 1: Can You Name All the Neighbors?
Try these before scrolling to the answers. Give yourself one point for each state you correctly name.
Q1: Colorado borders 7 states. Can you name all seven?
Q2: Kentucky borders 7 states. Name them.
Q3: Pennsylvania borders 6 states. Which ones?
Q4: Which state borders only one other state?
Q5: Two states border exactly two other states. Name both.
Answers: Round 1
A1: Colorado borders Wyoming, Nebraska, Kansas, Oklahoma, New Mexico, Arizona, and Utah. The last one — Arizona — trips people up because the two states meet only at a single point: the Four Corners monument, where Colorado, Arizona, New Mexico, and Utah all touch.
A2: Kentucky borders Illinois, Indiana, Ohio, West Virginia, Virginia, Tennessee, and Missouri. The Ohio River forms most of Kentucky's northern border, creating the boundary with three states (Ohio, Indiana, Illinois).
A3: Pennsylvania borders New York, New Jersey, Delaware, Maryland, West Virginia, and Ohio.
A4: Maine. Its only land neighbor is New Hampshire. (Alaska and Hawaii have zero US land borders, but Maine is the only contiguous state with just one.)
A5: Washington (borders Oregon and Idaho) and Rhode Island (borders Connecticut and Massachusetts). Some sources count Rhode Island as bordering New York via a water boundary in Block Island Sound, but by strict land borders, it's two.
Trivia Round 2: Border Quirks
Q6: Which state has the longest border with another single state?
Q7: Four states meet at a single point. Where is this, and which states are they?
Q8: Which US state border is defined by a perfectly straight line that runs for over 360 miles?
Q9: Which two states share the shortest border?
Q10: A small section of Minnesota is only accessible by land through Canada. What is it called?
Answers: Round 2
A6: Montana and North Dakota share a border of approximately 211 miles — one of the longest interstate boundaries. The California-Nevada border is also extremely long at roughly 400+ miles, though the exact measurement depends on how you account for Lake Tahoe and mountain terrain.
A7: The Four Corners: Utah, Colorado, Arizona, and New Mexico. It is the only point in the US where four states meet. The monument was placed in 1912 and has been surveyed multiple times to confirm its accuracy.
A8: The border between Montana and North Dakota/South Dakota is defined by the 49th parallel (Montana-Canada) and the 46th parallel (Montana-Wyoming), but the longest straight-line state border in the contiguous US is the border between North Carolina and Tennessee — wait, that one follows mountain ridges. The answer many expect is the western border of the Dakotas with Montana, but the cleanest example is the perfectly straight northern border of Colorado, running 365 miles along the 37th parallel from Kansas to Utah.
A9: Missouri and Oklahoma share a border of about 3 miles in the far northeast corner of Oklahoma. New York and Rhode Island technically share a water boundary but not a land one. Another extremely short border is between Arizona and Colorado at the Four Corners point, which is essentially zero-dimensional.
A10: The Northwest Angle — a small peninsula that juts north of the 49th parallel into Lake of the Woods. It resulted from an 18th-century mapping error in the Treaty of Paris (1783). About 119 people live there, and reaching it by road from the rest of Minnesota requires driving through the Canadian province of Manitoba.
Why Borders Look the Way They Do
Western state borders tend to be straight lines because they were drawn by Congress on paper before the land was fully surveyed or settled. The 37th parallel defines Colorado's southern border. The 42nd parallel separates Oregon from California. These geometric borders reflect political convenience, not geographic reality.
Eastern state borders, by contrast, follow rivers, mountain ridges, and colonial-era survey lines that respected (or at least acknowledged) natural features. The Ohio River defines Kentucky's northern border. The Appalachian ridge separates Virginia from West Virginia. The Connecticut River once separated Connecticut from Massachusetts. These borders are more complex, more irregular, and more interesting.
The result: western states tend to have fewer neighbors (big rectangles don't touch many other shapes), while eastern and central states — smaller, irregularly shaped, and packed together — border more neighbors.
Full Neighbor Count by State
8 neighbors: Tennessee, Missouri. 7 neighbors: Colorado, Kentucky. 6 neighbors: Arkansas, Idaho, Iowa, Nebraska, New York, Pennsylvania, South Dakota, Wyoming. 5 neighbors: Alabama, Georgia, Illinois, Indiana, Maryland, Massachusetts, Michigan, Mississippi, Montana, Nevada, New Mexico, North Carolina, Ohio, Oklahoma, Utah, Virginia, West Virginia, Wisconsin. 4 neighbors: Arizona, Connecticut, Delaware, Florida, Kansas, Louisiana, Minnesota, New Hampshire, New Jersey, North Dakota, Oregon, South Carolina, Texas, Vermont. 3 neighbors: California. 2 neighbors: Rhode Island, Washington. 1 neighbor: Maine. 0 neighbors: Alaska, Hawaii.
Put Your Knowledge on the Map
Now that you know which states touch which, test whether you can actually find them. Just States challenges you to click each state on an interactive map. GeoProwl's daily puzzle uses real federal data as clues — population, agriculture, climate, parks — so knowing a state's neighbors helps you triangulate from regional hints. And our Fast Facts pages have the full data profiles to explore after you play.