Convert furlong (US survey) to nautical mile (international) Online | Free Length Converter

Furlong (US Survey)

The furlong (US survey) is a traditional unit of distance used in U.S. land surveying, defined as 1/8 of a U.S. survey mile, or exactly 660 U.S. survey feet. Since one U.S. survey foot equals approximately 0.3048006096 meters, the US survey furlong is about 201.1684 meters long.

While the difference between the US survey furlong and the international (standard) furlong is extremely small (just a few micrometers), it was significant in precise land measurements, particularly in legal and cadastral surveying contexts.

Key Conversions:

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  1 US survey furlong = 660 US survey feet

  
  
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  1 US survey furlong ≈ 220 yards

  
  
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  1 US survey furlong ≈ 201.1684 meters

  
  
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  8 US survey furlongs = 1 US survey mile

  
  

As of 2023, the U.S. has officially deprecated the use of the survey foot (and by extension the survey furlong) in favor of the international foot, but it may still appear in historical and legal documents.

Nautical Mile (International)

A nautical mile (international) is a unit of measurement used primarily in maritime and aviation contexts. It is defined as 1,852 meters or 1.852 kilometers, which is approximately 1.1508 statute miles. The nautical mile is based on the Earth's geometry, representing one minute of latitude along any meridian. This makes it particularly useful for navigation, as distances on charts and GPS systems often relate directly to degrees of latitude and longitude. The international nautical mile was officially adopted by the United States in 1954 and is now used worldwide for consistency in global navigation. It is closely linked with the knot, a unit of speed equal to one nautical mile per hour. The standardization of the nautical mile has greatly simplified communication and coordination in international travel, trade, and defense across oceans and airspace. Its use continues to be essential in global navigation systems today.