Naturalization documents can often prove to be very helpful for anyone doing research on their immigrant ancestors. The process usually had three stages: declaration of intent, petition for naturalization and certificate of naturalization, with the immigrant usually applying at their local courthouse to become a US citizen.
To add to Buggy genealogy in this area, I have compiled all the naturalization indexes for the New York southern and eastern districts from the footnote.com website. This covers the courts in New York City. In all, 22 men are listed in the indexes and cover the years 1857-1892.
If anyone would like to add naturalization information for any Buggy not listed then a comment is most welcome.