Some attribute labels were renamed and attribute formats were altered. 1990 Census Tract boundaries of Washington State as recorded by the US Bureau of the Census. Census tract numbers range from 0001 to 9999 and are unique within a county or equivalent area. The U.S. Census Bureau reserves the census tract numbering range of 9400 to 9499 for use by American Indian area participants in situations where an American Indian entity crosses county or state lines. The U.S. Census Bureau uses suffixes to help identify census tract changes for comparison purposes.
Local participants have an opportunity to review the existing census tracts before each census.
If local participants split a census tract, the split parts usually retain the basic number, but receive different suffixes. In a few counties, local participants request major changes to, and renumber, the census tracts. Changes to individual census tract boundaries usually do not result in census tract numbering changes. Leading zeros are shown on machine-readable products, but are not shown in printed reports or on census maps. Suffixes smaller than 10 have a leading zero.