And then there are chains. An acre (the amount of land a man can plow in a day) is a chain wide and ten chains long. A chain is 66 feet long, a tenth of a furlong.

But wait, chains are composed of links. Some demented individual had heard of decimalization but didn't quite get the concept so he divided the chain into 100 links. This makes the link a super convenient 7.92 inches. Considering that math education back in that day was even worse than it is today, one would think they would have gone for something more integerial like say 66 links.