I once read that the Romans were masters of building roads that stretched long distances in a straight line like the Fosse Way road in Britain.

I never thought much of it until I watched Canada & The United States: Bizarre Borders Part 2 where the person mentions that the border is about as straight as a pre-GPS civilization could make, and as someone who has never attempted to draw a straight line over a long distance, I never thought of all of the problems that you would run into.

How did the Romans build straight roads that stretched very long distances?

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    No idea on the how, but at some point they realized that their obsession with straight roads was counterproductive. Going straight up and down a hill, or building a bridge over every little river or pond you may find in your way isn't either the smartest thing to do, nor the more cost effective.
    – yannis
    Jun 6, 2013 at 16:01
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    @YannisRizos Yes, I also read about that. The idea was that you build the road once and use it a million times so having it straight means less travel for the user than having him go around it which they thought would save them resource and time in the long run.
    – Caesar
    Jun 6, 2013 at 17:23
  • Important in having straight roads is the desire and willingness to have them. Straightness demands hill leveling and valley filling or bridging which is far more expensive than following contours. || The biblical "every valley shall be filled and every hill ..." is an allusion to roads made then for kings to travel on - again, an expensive prestige exercise. || On a London-Bangkok flight we flew over India and I took photos from ~= 35,000 feet. I showed a photo to a cousin who said, not knowing the location, "Those roads are originally British or Roman". I asked why. "They're straight". Apr 12, 2019 at 14:24

2 Answers 2


The simple answer is that they used a form of surveying tool called a groma. This basically consisted of two pieces of wood nailed together to form a square cross with right angles in all corners. Each piece of wood had lead weights attached to the end, and they determined they had a straight line when the lead weight from one piece of wood lined up with the one in front of it. Wood posts would be used to stake out the boundaries of the road in order to help maintain a straight line over an extended distance.

As an interesting side note, I found another source that indicated that Roman soldiers carried a tool such as a hatchet, pick, or spade in addition to his more traditional gear. When there was a need to build roads, the engineers would take groups of soldiers to use as laborers. This served a dual purpose of keeping the men in shape while also keeping them out of trouble.

  • They weren't called Marius's Mules for no reason. Caesar could as easily have echoed Erwin Rommel, from Infantry Attack: "Even on the attack I found the spade the equal of the rifle." May 7, 2015 at 4:03
  • The same surveyors and tools were used to lay out the camps and forts, which followed a standardized plan. Apr 12, 2019 at 19:53

Here is an interesting and well-cited article from Ferris State University College of Technology Surveying Engineering (there's a name that flows from the tongue) covering the technical aspects of ancient Roman surveying techniques.

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    Link-only answers are susceptible to link-rot, which renders them useless. Also, some people prefer not to click links to external sites. Please paraphrase/quote the article (or relevant) portions in this answer. As it stands now, this answer in itself does not answer the question at all.
    – Luke_0
    Jun 6, 2013 at 17:47
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    See meta.stackexchange.com/q/92505/192187 for example. The policy has been in place for quite a while.
    – Luke_0
    Jun 6, 2013 at 18:07
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    Yes, but paraphrasing or quoting relevant portions here would solve that.
    – Luke_0
    Jun 6, 2013 at 18:29
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    @Luke Interesting link to MSO that you gave there. The second-highest voted answer there is quite reasonable, in my opinion. In brief, first drop a friendly (!) comment prodding the Answerer to add some content. When you critique and downvote in one fell swoop, it gets people's backs up, especially if yours is the first vote. Jun 6, 2013 at 18:39
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    @RISwampYankee (and everyone else): This would be best discussed on Meta. While the general policy is that link only answers are not preferable, there's no reason why we can't establish our own policy on History (although, chances are we'll end up with more or less the same policy).
    – yannis
    Jun 7, 2013 at 4:35

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