Online New York City Naturalization Records and Indexes

The Online New York Naturalization Records Guide has two pages:
New York City Naturalization Records (this page) and New York State Naturalization Records (next page)

Online New York City Naturalization Records and Indexes
There are a variety of courts in New York City where naturalizations took place. You may have to check more than one index. Some indexes and records may not yet be online. Some of the listings here may also include counties ouside of NYC.

The New York City Boroughs of today are Manhattan (New York County), the Bronx (Bronx County), Brooklyn (Kings County), Queens (Queens County), and Staten Island (Richmond County).

New York City Naturalization Indexes and Records at Ancestry (these require payment):

New York, State and Federal Naturalization Records (Indexed), 1794-1943 for courts in all 5 NYC boroughs plus nearby counties in Southern New York; includes digitized records from the NYC branch of the National Archives; coverage varies by court (has over 9 million records)

New York: Index to Petitions for Naturalization Filed in New York City, 1792-1989 includes digitized images of the index cards; has over 1.6 million entries from all 5 New York City boroughs
New York County Supreme Court Naturalization Petition Index, 1907-1924 (Manhattan)
Index to Declaration of Intent for Naturalization: New York County, 1907-1924 (Manhattan) has nearly 675,000 listings
The above 4 databases (and Ancestry's Southern District database listed below) are included in a subscription to Ancestry's U.S. genealogy records collection

General New York Naturalization Records and Indexes...

New York City Naturalization Records Indexes
Naturalization Records from Queens and the Bronx (free) includes digitized images of the naturalization records
Bronx County: also see the Southern District of New York section below
Kings County (Brooklyn) Naturalization Index, 1907-1924
Kings County: also see the Eastern District of New York section below
Queens County: see the Eastern District of New York section below
Richmond County Naturalization Database, 1883-1959 coverage varies by type of document
Richmond County (Staten Island): also see the Eastern District of New York section below
New York, U.S. District and Circuit Court Naturalization Records (at FamilySearch/free) includes National Archives Microfilm Publications M1972 (Southern District Petitions) and M1879 (Eastern District Petitions)

Southern District of New York - Manhattan and the Bronx; also: Columbia, Dutchess, Greene, Orange, Putnam, Rockland, Sullivan, Ulster and Westchester Counties

Scanned Records - Southern District...
- Petitions for Naturalization From the U.S. District Court for the Southern District of New York, 1882-1944 (at Ancestry/requires payment) indexed; includes images from NARA Microfilm Publication M1972

Scanned Indexes - Southern District...
- Southern District Court of New York Naturalization Records Index, 1824-1959
- New York, Southern District Naturalization Index, 1917-1950 at FamilySearch; from NARA Microfilm Publication M1675

Eastern District of New York - Brooklyn, Queens and Staten Island; also: Nassau and Suffolk Counties

Scanned Records - Eastern District...
- See "New York, State and Federal Naturalization Records" above

Other New York Genealogy Resources...

Online New York City Death Records, Obituaries and Cemetery Burials

Online New York City and State Birth and Marriage Records Indexes