The U.S. Indian Census Schedules, 1885-1940 are available online through Ancestry.com. (This requires a subscription.)
Here is the descriptive information given by Ancestry.com for this database:
Source Information: Ancestry.com. U.S. Indian Census Schedules, 1885-1940 [database on-line]. Provo, UT, USA: The Generations Network, Inc., 2007. Original data: Indian Census Rolls, 1885-1940; (National Archives Microfilm Publication M595, 692 rolls); Records of the Bureau of Indian Affairs, Record Group 75; National Archives, Washington, D.C. About U.S. Indian Census Schedules, 1885-1940 This database contains an index to the Indian census rolls from 1885-1940. Information contained in this database includes: name (Indian and/or English), gender, age, birth date, relationship to head of family, marital status, tribe name, agency name, and reservation name.
This database contains an index to the Indian census rolls from 1885-1940. Information contained in this database includes:
Name (Indian and/or English)
Relationship to head of family
Agency and reservation name
Other information about an individual, such as degree of Indian blood, as recorded in the later census years, may be available on the original record. Be sure to view the corresponding image in order to obtain all possible information about an individual.
The Indian Census schedules are census rolls usually submitted each year by agents or superintendents in charge of Indian reservations, as required by an act of 4 July 1884 (23 Stat. 98). The data on the rolls varies to some extent. For certain years, including 1935, 1936, 1938, and 1939, only supplemental rolls of additions and deletions were compiled.
There is not a census for every reservation or group of Indians for every year. Only persons who maintained a formal affiliation with a tribe under federal supervision are listed on these census rolls.
Most of the rolls for the year 1940 were retained by the Bureau of Indian Affairs and are not included in this database. Rolls were not required to be submitted after 1940 so only a few post-1940 records are included here.
Notes about Searching the Censuses:
When browsing this large collection, it is important to note the following:
1) Family groups are listed together and are sometimes listed alphabetically by surname of the head of the family, but often there is often no discernible order to the listing of families.
2) Currently accepted spellings of tribal names have been used in the list below. In the census rolls themselves, obsolete spellings are often used; and the name of a tribe may be spelled several ways in different rolls. Sometimes even the name used for a tribe was changed from year to year.
Some of the above information was taken from:
Curt B. Witcher and George J. Nixon, "Tracking Native American Family History," in The Source: A Guidebook of American Genealogy, ed. Loretto Dennis Szucs and Sandra Hargreaves Luebking (Salt Lake City: Ancestry, 1997).
Publication Details of Indian Census Rolls, 1885-1940, National Archives, Washington, D.C.