Online Resources

An Introduction to Online Research Resources

New York City has extraordinary resources for hunting down information about building histories. Much of that work still has to be done in archives, city offices, libraries and historical societies, but in the past decade many of these resources have gone on-line, making it possible to do some of the research without having to visit the city. Even when the resources are print only, on-line catalogs make it possible to plan an efficient research visit to the city.

Below you will find some basic information on how to research New York buildings, followed by sets of links to various resources.

Please note: These resources are just the beginning. There are thousands of resources, and new sites are going on-line all the time. For a more exhaustive treatment, including listings of resources with contact information and web sites, detailed explanations on understanding the relevant documents, and instructions on visiting and using the relevant repositories, please consult The Urban Genealogy Handbook (available 2016  – to be notified when it becomes available, please send us an e-mail).

Existing building histories

Before starting out, check to see if the building you’re researching is either 1) listed on the National Register of Historic Places, or 2) designated as a landmark by the New York City Landmarks Preservation Commission (LPC). If it is, then an historical report already exists, and is available to researchers.

National Register

If the building is on the National Register, it is possible to obtain a copy of the historical report (called the “nomination”) on-line (this is true for any building in New York State). The New York State Historic Preservation Office (SHPO) in Albany maintains an on-line National Register database and what it calls its document imaging project. At the web site, click on “Online Resources” and then “Document Imaging” to find a copy. This can take some doing – you have to come up with the right name or address for the listing, and the system isn’t very intuitive. One approach is to look under the county (Manhattan=New York County, Brooklyn=Kings County, Staten Island=Richmond County, Bronx=Bronx County, Queens=Queens County). Click on “Basic Criteria,” enter only the county name, and then click on “Results,” and then just page through the listings. If the building in question is an individually listed historic resource, you will find its nomination individually listed on the site. If the building is within an Historic District, however, you’ll need to find out the district’s name.

New York City landmark

The simplest way to determine whether your building is a designated landmark is via the BIS system, see below under Buildings Department information. If it is, there will be a “designation report,” ranging in length anywhere from a few pages to hundreds of pages (for historic districts). These are now all available on the Landmarks Preservation Commission’s web site. Each designation report is backed up by a research file, which can be consulted on-site by appointment.

General information and mapping

NYCityMap – a web site maintained by New York City. This should be your first stop. Enter the address and borough of the building you’re researching in the search bar (as an example, use 350 Fifth Avenue, which is the Empire State Building), click “search,” and you’ll have a page with a map showing the building’s location, and links to all kinds of information about the building and its neighborhood. NOTE: Be sure to locate the building’s block and lot number – this is the key to all property records in New York City – buildings may have more than one street address, but only one block and lot number.

Early Real Estate Insurance Maps – these are available on the New York Public Library web site.

Online instructions

Several on-line resources offer instructions in conducting research into building histories:

A Guide to Researching the History of a New York City Building. This is an article by Christopher Gray, author of the New York Times “Streetscapes” columns.

Bulletin No 39, Researching a Historic Property The official listing of the nation’s historic buildings is the National Register of Historic Places. The National Register publishes informational bulletins. Bulletin No. 39 (Eleanor O’Donnell, 1991, revised 1998) is available on-line in its entirety. Though geared specifically to filling out an official property nomination to the National Register, it is also a very helpful overview of sources and methods.

Guide to researching New York City buildings A guide on the web site of Avery Library at Columbia University.

Researching an Architect or Building, A short (two-page) explanation for researching architects, available on-line from the American Institute of Architects.

Buildings Department information

The main site for municipal information on New York City buildings is the Building Information System (BIS) of the New York City Buildings Department. Once there, check to be sure you have the correct address. Be sure also to note the “Tax Block” and “Tax Lot” numbers – all New York City property records are keyed to the “Block and Lot” system, and you’ll need those numbers for any future research. Note also that this page has an entry for “Landmark Status” – a quick way to determine if the property is a designated city landmark (though this does *not* automatically mean the property is also listed on the National Register).

At the bottom of the page, there is a box for “Actions.” In the box labeled “Enter Action Type,” type in the letters “NB” – this stands for New Building Application – and click on “Show Actions”. Every new building in New York requires a New Building Application (in Manhattan, starting in 1866, in Brooklyn starting in 1878, in the West Bronx starting in 1874, and everywhere else starting in 1898). Each NB application is identified by an NB number.

If we take as an example the Empire State Building (350 Fifth Avenue): The NB number for the Empire State Building is NB 31-29. This translates as the 31st new building application filed in 1929. With that number, it is possible to access very detailed information from the application itself (available at the Buildings Department, or in some cases at the Municipal Archives, see below for that web site).

Office for Metropolitan History New Building search In most cases, the BIS listing of actions is as far as you can go on-line. But thanks to Chris Gray (see above under “online instructions”), if the building in question was constructed in Manhattan between 1900 and 1986, it’s possible to get a summary of the NB. Gray operates the “Office for Metropolitan History” web site. He arranged to collect the basic information on all Manhattan NBs during those years, and had them entered into a database, which he maintains on-line, where it is freely available to researchers. On the opening page, click on “SEARCH The Building Permits Database, 1900-1986.” Again, using the Empire State Building as an example – since it falls into this period – enter its NB. For NB 31-29, enter “1929” in the box marked “Year,” and “31” in the box marked “DOB NB#.” In this case, you’ll see 10 entries, because the search engine will turn up *any* NB number that starts with “31” – including “315,” etc. Find “Year 1929 DOB NB#31 (it’ll be the third one on the list), and there you will find a summary of the application. Notice that it’s described as a 55-story office building – that’s what the original application called for. Note also that the information includes cost, name and address of owner (“o”), and name and address of architect (“a”).

This system isn’t foolproof – sometimes the NB numbers are simply missing, sometimes there are several NB numbers (reflecting earlier buildings), sometimes the NB numbers refer to applications for projects that were never built, and sometimes, as with the Empire State Building, the original application was modified along the way. To nail down the information it is still necessary to consult the actual documents. But this is a good way to get started – chances are, the building at 350 Fifth Avenue was built beginning in 1929, to designs by Shreve & Lamb (and in fact, it was).

ProQuest periodicals on-line

Search the New York Times – and dozens of other newspapers – plus dissertations, journals, and hundreds of other sources. The entire New York Times, going back to 1851, is an exceptionally useful resource, as the Times has always covered real-estate in great detail. The entire newspaper has been optically scanned into a database that can be searched by word. ProQuest is a subscription service, but generally available in major public libraries. Ask a librarian how to access the service.

In the case of the Empire State Building, we would search for “350 Fifth Avenue” in the date range of, say, 1929-1931. As it happens, this building rarely is referred to by its address, so you won’t find much. But search on its name, “Empire State Building,” and you’ll find an article called “Smith to Help Build Highest Skyscraper” – and you’ll be on your way.

The Brooklyn Daily Eagle has also been scanned, and is available online, through 1902, courtesy of the Brooklyn Public Library.

There’s another source for on-line newspapers in New York State, and it includes the Eagle well into the 20th century, along with countless other local New York State papers (and also the New York Times):

Real Estate Record and Guide: This real-estate-industry newspaper is invaluable, and much of it has been scanned and made available on-line by Columbia University.

Various useful government sites

New York City Government

Federal Government

Libraries, museums and historical societies

Photos on-line at the New York Public Library

 Other photo resources

Finding aids


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