15 C.F.R. § 70.1 Cutoff dates and effect on enumeration and data tabulation.
Title 15 - Commerce and Foreign Trade
For the tabulation and publication of data from the Census 2000 of Population and Housing, the Bureau of the Census will recognize only those boundaries legally in effect on January 1, 2000 that have been reported officially to the Bureau of the Census no later than March 1, 2000. The Bureau of the Census enumerates respondents on the date of the decennial census as residing within the legal limits of municipalities, county subdivisions, counties, States, and equivalent areas as those limits exist on January 1, 2000.
Title 15: Commerce and Foreign Trade
PART 70—CUTOFF DATES FOR RECOGNITION OF BOUNDARY CHANGES FOR THE CENSUS 2000
§ 70.1 Cutoff dates and effect on enumeration and data tabulation.

