A good part of writing is research. The internet is a good source, but isn’t always reliable. Researchers know to follow up internet resources. Look in their bibliography where they got their information and the listing of books. If a writer writes a non-fiction book, they usually have to provide a proposal that entails a bibliography as proof of information. Here are a few research sites:
loc.gov Library of Congress chronicles American newspaper collections, catalog of manuscript collections, American Memory collections, and digital images of America’s past.
http://www.hti.umich.edu/m/moagrp This is a digital library of the 19th century which includes 10,000 books and 50,000 journal articles.
http://www.castlegarden.org NY Castle Garden is the immigration center with a database of 11 million immigrants from 1820-1892 when Ellis Island opened.
http://www.itd.nps.gov/cwss Civil War Soldiers and Sailors System- this site includes background on the social, economic, political, and military aspects of the Civil War.
http://www.usgs.gov/pubprod This is the US Geological site that has 57 printable maps for ancestral places.
http://www.archives.gov/ This is the National Archives & Records Admin. site. It contains useful information from genealogy to White House tapings.
http://www.newspaperabstracts.com This site hosts pages of abstracts and extracts from historical newspapers.
Many states have their own library systems for history but an invaluable portal to the world’s non-virtual library is the WorldCat with more than 1.5 billion items in libraries around the world. Look it up @ worldcat.org.
There are numerous genealogy sites that are also helpful for research.