The censuses of 1875, 1885 and 1900 are preserved in the regional state archives in their original version; the others are in the National Archives.
The three major nominative censuses from 1801, 1865, and 1900 are made available on the internet at The Digital Archives. You can also find portions of the other censuses there. The 1910 census will be available from December 1 2010. The Norwegian Historical Data Centre has also registered and posted online a significant amount of census data. The digitization of the censuses has greatly facilitated access to this information. Users no longer need to know where people lived in order to find them in the records. You can do a search on a name across the entire country. You can also find useful and interesting background information. With time, more census data will be made available on the internet.
In general, the censuses have been made accessible to the public on microfilm or microfiche, which are found in the National Archives, the regional state archives or at the local libraries. Hard copies of the censuses up to 1801 are found in the National Archives. To varying degrees, the national state archives retain copies of the later censuses from their own districts. In addition, local historical journals and yearbooks have published several censuses. More information on this can be found in the libraries.