Census Block Boundaries 2010

From the 2022 Census TIGER/Line Technical Documentation: Census blocks are statistical areas bounded on all sides by visible features (e.g., streets, roads, streams, and railroad tracks), and by non-visible boundaries (e.g., city, town, township, county limits, and short line-of-sight extensions of streets and roads). Generally, census blocks are small in area (e.g., a block in a city). Census blocks in suburban and rural areas may be large, irregular, and bounded by a variety of features (e.g., roads, streams, and/or transmission line rights-of-way). In remote areas, census blocks may encompass hundreds of square miles. Census blocks cover all territory in the United States, Puerto Rico, and the Island Areas. Blocks do not cross the boundaries of any entity for which the Census Bureau tabulates data. (See Figures 12 and 13). Census Block Numbers—Census blocks are numbered uniquely within the boundaries of each state, county, census tract with a 4-character census block number. The first character of the tabulation block number identifies the block group. A block number can only be unique by using the decennial census state (STATEFP<yr>), county (COUNTYFP<yr>), census tract (TRACTCE<yr>), and block (BLOCKCE<yr>)+. There is no consistency in block numbers from census to census.摘自2022年美国人口普查局TIGER/线（TIGER/Line）技术文档： 普查区块（census blocks）是指四周以可见地物（如街道、道路、溪流与铁路轨道）及无形边界（如市、镇、乡、县界，以及街道与道路的短视距延伸段）为界的统计区域。一般而言，普查区块的面积较小（例如城市中的街区）。郊区与农村地区的普查区块则可能面积较大、形状不规则，且以多种地物作为边界（例如道路、溪流和/或输电线路通行权区域）。在偏远地区，单个普查区块的覆盖范围可达数百平方英里。 普查区块覆盖美国、波多黎各及各岛屿地区的全部领土，且不会跨越美国人口普查局进行数据汇总的任何行政实体的边界。（详见图12与图13） 普查区块编号——普查区块会在每个州、县、普查片区（census tract）的范围内，以4位字符的普查区块编号实现唯一标识。汇总区块编号的首字符用于标识区块组（block group）。仅当结合十年一次人口普查的州代码（STATEFP<yr>）、县代码（COUNTYFP<yr>）、普查片区代码（TRACTCE<yr>）与区块代码（BLOCKCE<yr>）+等标识时，区块编号才具备唯一性。不同十年一次人口普查的区块编号体系并不具备一致性。