The New York Public Library's Irma and Paul Milstein Division of United States History, Local History and Genealogy, just a few blocks north of the Graduate Center in the 42nd Street Library, is one of the largest genealogical collections in the U.S. and the ideal place to to conduct in-depth research on people, places, and events in NYC and beyond.
The Milstein Division's Research Guides, including Genealogical Research at the NYPL, Genealogy Research Tips: Breaking Through Brick Walls and Getting Past Dead Ends, and The Great Obituary Hunt highlight the best resources and offer strategies for finding elusive information.
The Library of Congress has one of the world's premier collections of U.S. and foreign genealogical and local historical publications, numbering more than 50,000 compiled family histories and over 100,000 U.S. local histories.
See the LC's Local History and Genealogy Section's Research Topics & How-To Guides for helpful information on the basics of genealogy research, and for finding sources to study particular ethnic groups and communities, women's history, and military history.
The Resources for Genealogists section on NARA's (National Archives & Records Administration) website includes helpful tools for navigating their vast holdings, a guide to using NARA's online genealogy resources, and links to Census, Immigration, and other government records. There are also helpful tutorials to help you find specific types of records.
Reclaim The Records is a not-for-profit activist group that uses state and federal Freedom of Information laws to obtain copies of genealogical and historical data sets from government agencies, libraries, and archives. They then make the data available to the public for free, without any copyrights or usage restrictions.
Browse and search the 2,000+ collections made available so far by Reclaim The Records in the Internet Archive. Included are indexes to birth, marriage, divorce, and death in several states, including New York, New Jersey, Vermont, and Maryland, among others.