What really counts, literally, are the figures in census blocks, block groups and tracts. Those make up the geographic building blocks the Census Bureau imposes on the landscape. The smallest unit, the block, is simply a place with people in it that has a definable boundary. It can be a city block, a 20-story apartment building, or a huge swath of the Bob Marshall Wilderness. Martin said the blocks function as a sort of checklist to ensure every bit of geography is searched for residents.
Places come more from people than administrative decisions.
Losing that people connection makes deciphering the origins of some communities difficult. For example, the 2000 census place list includes Heron and Herron. What at first seems a bureaucratic typo is really two separate communities. The community of Herron, with 100 people, is a suburb west of Havre. The places that didn't make place status include many of recent fame or notoriety.