frequently asked questions about the

1. What are the dimensions of the acre?

“I just wanted to know what are the dimensions of an acre—how many feet wide and long?”

“If an acre is a square or rectangular why doesn't anybody on the web know what the measurements are in feet, not sq. feet. I have looked in about 1000 different places and no one has an answer that simple.”

“If I am to measure an acre as length x width what would that measure be? I have looked up many sites but cannot find this measurement.”

Since medieval times the acre hasn't had any set dimensions. It is purely an area of 43,560 square feet. The two sides of a 1-acre rectangular lot can be any lengths as long as multiplying one by the other gives 43,560 (if they are measured in feet). For example, imagine a sidewalk 5 feet wide. If it were (43560 ÷ 5 = ) 8712 feet long it would take up an acre, a long skinny acre. On the other hand, if the 1-acre lot were a square, its sides would be only 208.7 feet.


2. What is the perimeter of an acre?

“Can you tell me [if the distance around] one acre of land is more than a mile? I want to purchase property, but I want the distance around the property to be at least 1 mile.”

Because the acre is a measure of area, it has no specific perimeter. For example, using the examples in question one, the perimeter of the long, skinny sidewalk acre would be 17,434 feet (more than 3 miles), but the perimeter of the square acre would be 835 feet. If you don't know the shape of the lot you can't determine the perimeter.


3. How are acres measured on hillsides?

“If I buy a hill, it being sold as 242 acres, how are the acres measured? Are they as if the hill were cut off and the land was level? Or up one side of the hill and down the other as if it were covered with a blanket and then the size of the blanket was measured?”

It's as if the hill were cut off and the land was level. To quote from an old authoritative surveying text:

Horizontal Lines. -- In surveying, all measurements of lengths are horizontal or else are subsequently reduced to horizontal distances. As a matter of convenience, measurements are sometimes taken on slopes, but the horizontal projection is afterward computed. The distance between two points as shown on a map then is always this horizontal projection.

Charles B. Breed and George L. Hosmer.
The Principles and Practice of Surveying, Vol 1.
New York: John Wiley & Sons, 1908.