State Archives can be a wealth of resources for the genealogist. Making a State Archive a destination point in your genealogy traveling plans can yield information regarding your ancestor that you had never thought existed. If you happen to have an enthusiastic Archivist to help you, then you have reached the gold standard.
If you are researching online, many of the State Archives websites have digitized documents, indexed information and have databases to search. I did contact the Arizona State Archives and discovered Ancestry.com is digitizing their records and according to the Archivist, those records will not be online to search from your home computer for 5 years, but you would be able to search by purchasing Ancestry's subscription or from a facility that has a Library Edition of Ancestry. That is too bad, I believe. If this will be the case for ALL of the State Archives I don't know. My advice is that you find the State Archives website of your state of interest and check it out. Some states don't have much. Others have a wealth of information. One word of caution: there is a website that comes up when you Google State Archives and it leads you to another subscription portal.
Missouri State Archives has a great deal of information on their site. You can check it out by going to
Census schedules for Missouri from 1830-1930
County and Municipal Records
Military Records of Missourians from the War of 1812 through World War 1, including more than 9 million pages related to the Civil War
Missouri's history under French & Spanish colonial rule, as a U.S. territory, and during early statehood
Photographs and Digital Collections
Resources for Family & Community History
State agency records
State government publications
Many of these are searchable databases.
From time to time, I will post State Archives websites that I have visited and checked out.
If you take a trip to one of these State Archives, we at The Traveling Genealogist would love for you to submit your research experience.