Far Off
The longest sailable straight line on Earth is 32,089.7 km long. It starts at Sonmiani in Pakistan and ends in Kamchatka, Russia, without touching land once. Over dry land, the longest straight line that crosses no water measures 11,241.1 km, from China’s Fujian province to Sagres in Portugal.
| Path | Distance | From | To |
|---|---|---|---|
| Over water | 32,089.7 km | Sonmiani, Balochistan, Pakistan | Karaginsky District, Kamchatka Krai, Russia |
| Over dry land | 11,241.1 km | Jinjiang, near Quanzhou, Fujian, China | Sagres, Portugal |
| Over land, looser rule | 13,573 km | Near Greenville, Liberia | Peninsula north-east of Wenzhou, China |
These are computed results, not feats of travel. Two researchers established them in 2018, and neither path has ever been travelled.
1. Over water: 32,090 km from Pakistan to Kamchatka
The path begins at Sonmiani, in the Las Bela district of Balochistan, Pakistan. It runs down the Indian Ocean, threads the gap between Africa and Madagascar, slips between Antarctica and Tierra del Fuego, climbs the full length of the Pacific and finishes in Karaginsky District, Kamchatka.
Detail. It stays in open water the whole way, which requires two very tight squeezes: the Mozambique Channel and the Drake Passage. The distance works out at roughly 80 percent of the Earth’s circumference. A ship following it would hold one constant heading from start to finish, yet it would set off heading south-west and arrive from the north.
2. Over dry land: 11,241 km from China to Portugal
The land path starts at Jinjiang, near Quanzhou in Fujian, on China’s east coast. It crosses Mongolia, Kazakhstan, Russia, Belarus, Poland, Austria, Switzerland and Spain before ending at Sagres, on Portugal’s south-western tip. Fifteen countries in all.
Detail. The line skirts Madrid, clips a corner of Austria, brushes the Swiss Alpine highlands, passes just north of Auschwitz in Poland and barely touches Ukraine. It is close to three times shorter than the water path, which says something blunt about how the planet is arranged: most of the Earth is ocean, and the continents are poorly lined up.
3. A third answer: 13,573 km from Liberia to China
Allow narrow crossings such as rivers and canals and the longest land line changes completely: 13,573 km from the coast near Greenville in Liberia to a peninsula about 100 km north-east of Wenzhou, China. Eighteen countries.
Detail. It crosses the Suez Canal, which rules it out under the stricter rule used for the previous path. It is the line sometimes sold as “the longest walk in the world”. Two rules, two answers, which is exactly why the definition matters more than the number when someone quotes one of these figures.
4. Who worked these out, and how
The water route started with a Reddit user called kepleronlyknows, who posted a map in 2012 claiming it showed the longest straight sail possible. Six years later Rohan Chabukswar, of the United Technologies Research Center, and Kushal Mukherjee, of IBM Research, decided to test the claim properly.
Detail. They used NOAA’s ETOPO1 global relief model and a branch-and-bound algorithm, publishing the result as Longest Straight Line Paths on Water or Land on the Earth, filed in April 2018. Their verdict: the computed path is visually identical to the one drawn on Reddit, so the 2012 map was right all along. The authors also state plainly that they do not recommend sailing or driving either route.
What a “straight line” means on a sphere
On a curved surface there is no straight line in the schoolroom sense. The shortest path between two points on a sphere is an arc of a great circle, a circle whose centre is the centre of the planet. The equator is one. So is every meridian. Every other line of latitude is not.
That arc is what “straight line” means here, and it is also the path aircraft fly. On a Mercator map a great circle looks bent, often dramatically so: the Pakistan to Kamchatka route reads as an enormous loop. The line is not warped, the map is. The same distortion is why Africa looks so small on a world map.
Why the water route is longer than half the planet
A great circle is about 40,075 km around. The greatest possible separation between two points measured along it is therefore 20,037 km, the distance between a place and its antipode.
The water route covers 32,090. The reason is that it follows the longer of the two arcs between its endpoints rather than the shorter one. Pakistan and Kamchatka are only about 8,000 km apart as the crow flies, but everything between them in that direction is land. The only fully sailable line goes the other way round the circle, some 288 degrees of arc.
Where the calculation stops being useful
ETOPO1 has a resolution of roughly 1.8 km. Anything finer than one cell, an islet, a reef, a sandbar, simply does not exist as far as the algorithm is concerned. The geographer Keith Clarke also noted that the model treats the Earth as a perfect sphere and ignores the equatorial bulge.
The land path has the mirror-image problem: it runs through mountains, deserts and conflict zones, and it steps over bodies of water smaller than the grid. It is a precise geometric answer to a geometric question, not an itinerary. For journeys you can actually buy a ticket for, see the longest train journeys in the world.
Mirror piece: the longest train journeys in the world. Going further: the 10 longest flights in the world, where you come out if you dig a hole through the Earth and the antipodes of France.
Frequently asked questions
What is the longest straight line you can travel on Earth?
Over water, 32,089.7 km from Sonmiani in Pakistan to Karaginsky District in Kamchatka, Russia, never touching land. Over dry land, 11,241.1 km from Jinjiang in China’s Fujian province to Sagres in Portugal. Both figures were computed in 2018 by Rohan Chabukswar and Kushal Mukherjee using NOAA’s ETOPO1 relief model.
Has anyone actually travelled either route?
No, neither one. They are optimisation results rather than expeditions, and the two authors explicitly say they do not recommend sailing or driving along them. The stretch between Antarctica and Tierra del Fuego, on the water route, is among the roughest sailing on the planet.
Why does a straight line look curved on a map?
Because a flat map has to distort a curved surface. On a sphere the most direct path is a great-circle arc, and the Mercator projection, which stretches the high latitudes to preserve angles, turns that arc into a curve on screen. The longer the route and the higher the latitudes it reaches, the more pronounced the bend.
How many countries does the longest land line cross?
Fifteen, between China and Portugal, including Mongolia, Kazakhstan, Russia, Belarus, Poland, Austria, Switzerland and Spain, with only a sliver of Ukraine. A different line, one that allows canal crossings such as Suez, runs 13,573 km from Liberia to China and crosses eighteen countries.
How can a straight line be longer than half the way around the Earth?
Because it follows the long arc of the great circle instead of the short one. A great circle is about 40,075 km around, so no two points are more than 20,037 km apart along it. The water route covers 32,090 km, roughly 288 degrees of arc, because the direct line between Pakistan and Kamchatka runs entirely over land.