Table 12-1. Development of UA Criteria From 1950 Through 1990
| 1950 |
Central place requirement
Incorporated place population of 50,000 or more (1940 census count)
Method of boundary delineation
Population estimates, precensus surveys, aerial photography
Density requirement
At least 500 dwelling units (approximately 2,000 people per square mile)
Place population in urban fringe
- Incorporated places with at least 2,500 people; no CDPs were included
- Smaller incorporated places with a concentration of 100 or more dwelling units whose density was at least 500 dwelling units per square mile
Other features
Exclaves of discontiguous nonplace territory within 1½ miles and connected by road
Number of UAs
A total of 157
|
| 1960 |
Central place requirement
- Incorporated place population of 50,000 or more using current census counts
- Twin cities rule (two contiguous incorporated places with a combined population of at least 50,000, the smaller of which must have at least 15,000)
Method of boundary delineation
Census results, small enumeration districts (EDs)
Density requirement
At least 1,000 people per square mile
Place population in urban fringe
At least 2,500 people; CDPs if at least 10,000 people (except New England)
Other features
- MCDs in New England, New Jersey, and Pennsylvania with at least 25,000 inhabitants or a population density of at least 1,500 people per square mile and a minimum total population of 2,500 became urban by special rule; this rule applied only to the 1960 census.
- Inclusion of indentations/enclaves
- First UAs in Hawaii and Puerto Rico
Number of UAs
A total of 213
|
| 1970
|
Central place requirement
- Incorporated place population of 50,000 or more using current census counts
- An incorporated city of 25,000 or greater population could qualify as a central place if it could combine with contiguous places of any size (but with a density of at least 1,000 people per square mile) to obtain a total population of at least 50,000.
Method of boundary delineation
Blocks (mail areas), small EDs (non-mail areas)
|
12-4Urban and Rural Classifications
