Ancestry.com: A very popular genealogy site on the web. There are portions of the site for members only.
Ancestry Library Edition: This product which must be used on a library computer is a searchable genealogical database that includes US census, military records, immigration records, and many other sources for tracing your ancestors.
Castle Garden: offers access to an extraordinary database of information on 12 million immigrants from 1820 through 1892, the year Ellis Island opened.
Ellis Island Records: Track immigrants entering via Ellis Island, and honored at the Statue of Liberty. Searching, and an e-mail newsletter, are free with registration.
Merrimack Historical Society: learn about this local historical organization
New Hampshire Historical Society: Provides information on numerous aspects of NH history.