Prior to 1970 the level of detail both in terms of topic and geographic reporting is much lower than for later years. Most files that are available are public use microdata files or files based on printed publications.
Historical Census Browser
This site provides a web-based interface to state and county data for census years 1790 through 1960. Users who wish to work with the data directly should use ICPSR Study, Historical, Demographic, Economic, and Social Data: The United States, 1790-1970. This study can be downloaded from the ICPSR website.
Files for FTP
ICPSR has the best collection of machine readable files for early census years. It includes Elizabeth Bogue tract data files for 1940, 50, and 60 for selected metropolitan areas (NYC available only for 1940) and states. The Bogue files are not microdata but summary data compiled from the print Census Tract reports
CU Data Catalog
Two of the ICPSR studies are stored in CU Data Catalog with study number 1960, one is the public use microdata and one is tract level data that reports only on selected characteristics of a subset of the population.
Because of the limited amount of data that is available electronically, it is important to be aware of what is in print.
Library's Decennial Census Collection
This is a detailed list of Columbia's print and CD-ROM holdings plus links to useful Web sites and reference sources. Note: Selected New York City tract volumes are available in the Data Service. These include 1990, 80, 70, and 60. There is only one copy of for 1950 and it is located with Lehman's collection of census volumes in that stacks at HA 201 C3.223:950.
Publications Specific to New York City
Census Tract Data on Population and Housing in New York City 1940 HA 730 .N5 W3 - Lehman Reference
Census Data With Maps for Small Areas of New York City, 1910-1960
HA 730 .N5 B68 1981 - Lehman Reference
Includes not only the published census data for NYC, but also unpublished census data and special tabulation performed by the NYC Planning Dept. Levels include block, tract, and health area for 1910-1960, as well as assembly district, statistical area, and sanitation district for some earlier censuses. All data, including maps, is on microfilm (F d901) located in Lehman Library.
Population of the City of New York, 1890-1930. HA 730 .N5 C5 1930 - Lehman Reference 317.8 N484 - Business AA9127 N4 C49 - Avery
Tabular presentation of data from several censuses, both Federal and New York State, with some data actually going back to 1790.
New York City Statistics
This is a list of print and online publications that report statistical information about New York City.
New York State Census
New York State conducted its own census in 1808, 1814 and 1822, though not in all counties. This link is to a CU Libraries Research Guide that describes what is available.
Related Reference Material
Geographic Areas Reference Manual
Although focused on the 1990 Census, this book provides a history of census geography and including information about areas like MCDs, CCDs, outlying areas, Indian lands, and blocks. This book is also available in print in the Data Service and in CLIO.