Iowa

The formal state archives program, maintained by the Iowa State Historical Society, has links to a number of smallish collections:

• Iowa County Maps
• Iowa Governors
• Historic Children's Diaries
• Iowa in World War II
• African American Women Students at the University of Iowa, 1910-1960
• Meskwaki Indian History
• Iowa Legislature
• Women’s Suffrage
• Photograph Samples

Some interesting topics, to be sure, but as I said, the collections are generally modest in scope.

However, for some mysterious reason, Iowa has some of the best free newspaper archives available online, allowing users to search through millions of articles covering the history of the state:

• Adams County Newspaper Archives, 1876-2000
• Cedar Rapids Newspaper Archives, 1857-1998.
• Charles City Daily Press, 1930-1931.
• Sioux County Newspaper Archives, 1872-2000.
• Des Moines Newspaper Archives, 1970-2007.
• Malvern and Mills County Archives, 1864-2002.
• Carroll Newspaper Archives, 1884-2007.
• Buffalo Center Tribune, 1894-2003.
• Muscatine City Directories, 1856-1959.

Few states offer such a rich online collection of fully searchable newspapers, so take advantage of Iowa's special crop.

Update! Turns out the University of Iowa hosts a pretty nifty archive of their own, the Iowa Digital Library. Not everything here is strictly Iowa-related, but then again, much of it is! Definitely worth an explore.