What's an acre?

We've been using the "acre" as a way of measuring land since the first plow dug into American soil. The area of an acre is a lot bigger than a few feet but much less than a square mile. So how did this moniker of measurement come to be?

Michael Pugh is a land expert with Ownerly, a real estate data company, and he's also interested in land history. He says the term "acre" comes from an old English word meaning "field". The measurement was decided by the amount of land that a team of oxen and a man could plow in one day.

"Historically, it's a long strip of land. It measures 660 feet by 66 feet so it's basically a 1x10 ratio," says Pugh. "The length of it was called a furlong, which is a furrow long, and that's how long a team could plow before needing a break and turning around to go back the other way."

Nowadays, a one-acre piece of land can be a square, a circle, or any shape, as long as it measures 43,560 square feet.
It's hard to visualize an acre but here's one way to do it.

"I think an easy for at least anyone who's watched a football game to understand is it's basically a little bit smaller than a football field," he explains. "If you go from an end zone to about the 10-yard line on the other side, so 90% of the football field, that's about the size of one acre."

In the 1860's, a pioneer could buy 160-acre tracts of land from the government and divide it into 40-acre parcels. If the farmer was too far away to be reached, it was usually because he was out plowing "the back 40" of the farm. And that's where that term came from.