City blocks vary in size, but the typical city block is from 310 to 323 feet in length. This equals approximately 16 or 17 blocks per mile.
Engineers typically use 100,000 square feet as an estimate for a city block, or about 2 1/4 acres. A city block is usually defined as the smallest unit of area that is surrounded by streets. Most are rectangular in shape, and enclose two rows of property lots, set back to back, with the fronts of each lot facing the street. In planned cities, streets are often laid out on a grid, and city blocks are often uniform. Older cities, that grew and developed over time, can have considerable variation in the size and configuration of the city blocks.