City block

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For other uses of this term, see city block (disambiguation).

A city block is a central element of urban planning and urban design. A city block is the smallest area that is surrounded by streets.

In most cities of the world that were planned, and did not develop and expand over a long period of time, streets are traditionally laid out on a grid plan, so that city blocks are square or rectangular. Since the spacing of streets in grid plans varies so widely among cities, or even within cities, it is impossible to generalize about the size of a city block. However, as reference points, the standard block in Manhattan is about 264 feet by 900 feet (about 80 meters by 270 meters), or slightly over five acres (two hectares); and in some U.S. cities standard blocks are as wide as 1/8 mile (660 feet or approximately 200 meters), or 10 acres (about 4 hectares) if square.

In most areas, cities have grown in a more amorphous manner rather than being planned from the outset. For this reason, an even pattern of square or rectangular city blocks is very uncommon in much of Europe.

In much of the United States and Canada, the addressing systems follow a block-number system, in which each block of a street is allotted 100 building numbers.

Image:City block.PNG

Diagram of an example of a rectangular City Block as seen from above, surrounded by streets. The block is divided into lots which were numbered by the developer as shown in red here and as shown in plats. The addresses on this example 800 block are shown in black and the adjacent blocks are the 700 and 900 blocks. An alley shown in light gray runs lengthwise down the middle of the block. Streets are shown in dark gray. Sidewalks are shown in light gray. Parkways are shown in green with walkways shown in light gray from every lot to the street.

In the 20th century, a popular feature in urban planning was the superblock. A superblock is much larger than a traditional city block and is typically bounded by widely spaced, high-speed, arterial or circulating routes rather than by local streets. Superblocks are generally associated with suburbs, planned cities, and the urban renewal of the mid-20th century; that is, in areas in which a street hierarchy has replaced the traditional grid. In a residential area of a suburb, the interior of the superblock is typically served by cul-de-sac roads.