Find secondary sources that will place your topic in a national context. Remember that the notes and bibliographies of secondary sources offer great citations for primary sources.
One approach is to explore the following subject headings:
Hudson River Valley NY and NJ History
The following sources are also good places to begin:
In addition to the sources mentioned below, which are specific to Poughkeepsie, you will want to consult primary sources in a broader context as well. For example, what were mainstream publications such as The New York Times or other popular magazines saying about the Hudson Valley?
Most of the old Poughkeepsie newspapers are in microfilm and are housed in microfilm room in rough chronological order.