Most land in the United States was originally measured and deeded using units that are no longer in common use. Chains, links, varas, rods, and furlongs appear constantly in old deeds, patents, and plats — and understanding them is a basic requirement for working with historical land records, boundary retracements, and metes-and-bounds descriptions.
These aren't arbitrary historical curiosities. They are precise, defined units with specific relationships to each other and to modern measurements. Once you know the conversions, working with them becomes straightforward.
The Gunter's Chain
The chain used in American land surveying is the Gunter's chain, invented by English mathematician Edmund Gunter in 1620. Gunter designed it specifically to make land area calculations easier: 10 square chains equals exactly 1 acre, which makes the math simple without a calculator.
1 chain = 66 feet (exactly).
That number is not arbitrary. Gunter chose 66 feet because it creates clean relationships across multiple units: 80 chains equals exactly 1 mile (5,280 feet ÷ 66 = 80). Ten square chains equals 1 acre. A furlong — the standard unit for agricultural fields — is 10 chains.
The physical chain had 100 links, each link being 0.66 feet (7.92 inches). This is why you see distances in old deeds expressed as “14 chains and 52 links” — the same way you might say 14.52 chains, but written out using the subdivisions of the physical instrument.
Links
1 link = 0.66 feet = 7.92 inches
100 links = 1 chain = 66 feet
Links are the smallest subdivision of the Gunter's chain. In old field notes and deeds, distances are often expressed as “chains and links” — so “5 ch 43 lk” means 5 chains plus 43 links, or 5.43 chains, or 358.38 feet.
To convert links to feet: multiply by 0.66.
To convert feet to links: divide by 0.66, or multiply by 1.515151...
Rods, Poles, and Perches
These three names refer to the same unit:
1 rod = 1 pole = 1 perch = 16.5 feet = ¼ chain = 25 links
The rod predates the Gunter's chain. It was originally the length of a rod or pole used to measure land, and it fits neatly into the chain system because 4 rods = 1 chain. You'll see it most often in older eastern states — New England deeds, colonial-era surveys, and records from the original thirteen states frequently use rods.
A square rod (sometimes called a “square perch”) is 272.25 square feet. There are 160 square rods in an acre.
Furlongs
1 furlong = 10 chains = 660 feet = 220 yards
Furlongs appear occasionally in large tracts, federal land survey descriptions, and early township plats. The name comes from “furrow long” — the length of a furrow in a standard plowed field under the old English open-field system. You're unlikely to see furlongs in typical property deeds, but they appear in historical records describing large land grants.
Varas
The vara is the unit most commonly encountered by surveyors working in Texas, the American Southwest, and former Spanish territory. It is a Spanish unit of length, and its exact value varies by state because different Spanish colonies established their own standards.
Texas vara
1 Texas vara = 33⅓ inches = 2.7778 feet
Texas vara is the most commonly used in American surveying. The Texas Legislature standardized it at 33⅓ inches. This is the value to use for any deed or survey from the Republic of Texas or the state of Texas.
1 labor (a common Texas unit of area) = 1,000,000 square varas ≈ 177.14 acres
1 league (sitio de ganado mayor) = 25 labors ≈ 4,428 acres
These area units — labors and leagues — appear constantly in Texas land grants, especially in South Texas and the Gulf Coast region where original Spanish and Mexican land grants were surveyed in varas.
California vara
1 California vara = 33 inches = 2.75 feet
California's vara is slightly shorter. It was standardized at 33 inches by California statute. When working with California rancho surveys or early California deeds, use this value rather than the Texas definition.
Other state varas
Florida, New Mexico, and other former Spanish territories have their own historical vara values, some of which were never formally standardized. When working in these states, the best practice is to check the state statutes and any controlling case law for the jurisdiction rather than assuming the Texas or California standard applies.
Other Units You May Encounter
Acres
1 acre = 43,560 square feet = 10 square chains
The acre is still the standard unit of land area in the United States. Its definition flows directly from the chain system: 10 chains × 1 chain = 10 square chains = 1 acre. This is not a coincidence — Gunter chose the length of his chain specifically to make this relationship work.
Miles and sections
In the Public Land Survey System (PLSS), the township-range-section grid that covers most of the United States west of Ohio:
1 mile = 80 chains = 5,280 feet
1 section = 1 square mile = 640 acres = 6,400 square chains
1 township = 36 sections = 23,040 acres
Meters
1 meter = 3.280839895 feet
1 foot = 0.3048 meters (exactly, by international definition)
Note: the U.S. Survey Foot (1 ft = 1200/3937 meters) was used in U.S. geodetic surveys until it was officially retired on December 31, 2022. All U.S. surveys completed on or after January 1, 2023 use the international foot (0.3048 m exactly). The difference between the two is about 2 parts per million — negligible for most purposes but significant at long distances and in high-accuracy geodetic work.
Quick Reference Conversion Table
| Unit | Feet | Chains | Meters |
|---|---|---|---|
| 1 link | 0.66 | 0.01 | 0.2012 |
| 1 rod / pole / perch | 16.5 | 0.25 | 5.0292 |
| 1 chain | 66 | 1 | 20.1168 |
| 1 furlong | 660 | 10 | 201.168 |
| 1 mile | 5,280 | 80 | 1,609.344 |
| 1 vara (Texas) | 2.7778 | 0.04208 | 0.8467 |
| 1 vara (California) | 2.75 | 0.04167 | 0.8382 |
Reading a Metes-and-Bounds Deed with These Units
Here is an example of the kind of language you'll find in an older Texas deed:
Beginning at a point on the east bank of Brushy Creek, being the southwest corner of the survey; thence N 45° E 42 varas to a cedar post; thence S 89° 30′ E 20 chains 14 links to an iron pin; thence S 0° 30′ W 25 chains to the south line; thence N 89° 30′ W 1320 varas to the place of beginning.
To work with this description, you need to convert all distances to a common unit before computing latitudes and departures. Working in feet:
- 42 varas × 2.7778 ft/vara = 116.67 ft
- 20 chains 14 links = 20.14 chains × 66 ft/chain = 1,329.24 ft
- 25 chains × 66 ft/chain = 1,650 ft
- 1,320 varas × 2.7778 ft/vara = 3,666.70 ft
With all distances in feet, you can compute the closure and plot the boundary normally. The SlateTablet unit converter handles all of these conversions automatically, including Texas and California varas.
Why These Units Persist
Chains, varas, and links didn't disappear when the U.S. adopted more modern standards. They persist for one simple reason: land descriptions are permanent. A deed written in 1858 in chains and varas stays in chains and varas. Every subsequent survey retracing that boundary must start from the original description and the original units.
When a client asks a surveyor to locate a corner from an 1880 deed, the surveyor must understand what the original surveyor measured, in the units they used, with the instruments they had. Converting everything to feet at the outset is fine for computation, but understanding the original units is the starting point.
A surveyor who doesn't know that a Texas vara is 33⅓ inches, or that the California vara is different, or that a rod and a perch are the same thing, is missing foundational knowledge that affects boundary retracement work across a large portion of the United States.
The Practical Takeaway
Most surveyors working in modern subdivisions and commercial work will rarely encounter chains or varas. But anyone doing boundary retracements, working with historical plats, handling land grant research, or practicing in Texas, California, or the Southwest will encounter these units regularly.
The conversions are fixed and exact. Learn them once and they apply everywhere.
- 1 chain = 66 feet = 100 links
- 1 rod = 16.5 feet = 25 links
- 1 Texas vara = 33⅓ inches
- 1 California vara = 33 inches
- 10 square chains = 1 acre
- 80 chains = 1 mile
If you work with these units regularly, the SlateTablet surveying unit converter converts between all of them — chains, links, varas, rods, feet, meters, and more — without requiring any manual calculation.