Acre

Acres is the term used to describe distances in. The map shows the acres and the people that live in them. To make the town perfect, a certain amount of trees and flowers in the acre spread apart evenly is needed.

In Animal Forest and Animal Crossing
In and, the player could only be in one acre at a time, but in  and , the map is more fluid, allowing the player to straddle the edges.

In Animal Crossing (GCN)
Acres are very similar to the ones seen in City Folk. There are 5x6 acres, each consisting of 256 squares for planting trees, flowers etc. The squares are arranged in 16x16 squares, making a total of 7680 squares, the largest amount in any game, possibly excluding Animal Crossing 3DS. There is 1/5 chance of finding a beehive in a regular oak/cedar tree in every acre (5 spawn daily), as well as one tree in every acre containing 100 bells and another containing some common furniture. There are also cliffs, which are present in every game, excluding Wild World.

In Animal Crossing Wild World
Acres still exist in Wild World, but they are not visible. In total, each acre in Wild World, there are 20 acres (opposed to Animal Crossing (GCN) and City Folk's 25), but each acre is still 16x16 squares. That means each acre is 256 squares in total and that also means the entire town is 5120 squares. In each acre, there is at least one regular tree that gives out 100 bells daily, when shaken. Additionally, in Wild World, there is also a 3/20 chance of encountering a swarm of bees when an ordinary tree is shaken (3 swarms spawn daily, not to be confused with a honeybee), and 1 regular tree also holds some common furniture, which falls out when the tree is shaken. Additionally, cliffs have been removed from Wild World.

In Animal Crossing City Folk
Acres are very similar to Wild World, and function in much the same way. There are still 16x16 squares, but there are only 5x5 acres, dissimilar to both it's predecessors. The ratio of beehives, furniture and bells per acre is identical to Animal Crossing (GCN)

In Animal Crossing 3DS
Very little is currently known about Animal Crossing 3DS, but it is sure to involve cliffs, unlike Wild World, which was for the original Nintendo DS. Due to the improved processing power and expanded cartridge memory of the Nintendo 3DS, the map may be bigger. However, it has not been confirmed.