The 1890 police census is available in two formats: a) digital databases, and b) microfilm.
Databases.
The Municipal Archives has digitized the complete collection of original surviving census books. The scanned pages are freely searchable, but, as of May, 2025, they have not been digitally indexed and are not keyword searchable. To access relevant pages, researchers must determine the Assembly and Election District numbers for the subject address.
Family Search makes available scanned images of the original microfilm, but this digitized collection is only viewable from computer terminals at Family History Center locations. A digital index of the 1890 police census is available at Family Search with a free membership. Note that the citation given in Family Search uses the term "volume" in reference to the number of the census books; also, the additional numbers in the citation are references to the microfilm collection at the Family History Library, and do not match the call numbers used by NYPL collections. It is unclear how much of the 894 census books are searchable on Family Search.
Ancestry Library Edition has indexed 26 of the 894 books, or only roughly 3 percent. Digital images of the census pages are not available. The book number and page number in the book are provided.
Microfilm.
Municipal Archives at 31 Chambers Street. 59 rolls of 894 books.
NYPL microfilm collections located in the central library on West 42nd Street and Fifth Avenue. These reels are duplicates of the microfilm at the Municipal Library. See the catalog record for the 1890 New York City police census, which details the numbers of missing books. Note that in the catalog record, the collection is described as totaling 54 reels, with a total of 108 missing books out of the original 1,008 - likely because the collection at NYPL is not a 100% duplication of the collection at the Municipal Archives. The reels are all assigned the same library classmark, *ZI-562, and are then arranged in the sequence of census books in the open cabinets in Room 119. No call slip or advanced request is necessary to access these microfilms.