German researcher Dietmar Staude has, according to The Wall Street Journal, made extensive use of “World War II air-raid records and aerial photographs to find unexploded bombs.” The story is worth a look for both the sheer novelty of Staude’s research method, which he perfected with the help of Air Force Historical Research Agency (Maxwell Air Force Base, Alabama) archivist Archie DiFante, and because it serves as a good reminder that archival research is a key feature of the complete research plan.
Retired records are sent to archives throughout the country according to applicable records retention schedules. The federal government is the largest single creator of records in the world and, as a result, operates the world’s largest archive system: 17 records centers in 9 regions throughout the country. Here's more information on the National Archives.
State records are kept in the state archive of the state in question which is sometimes, but not always, managed by the state library. Counties and cities each operate their own archives, as well. Nongovernmental archives, maintained by local historical societies and university librarians are also common. The uses for archived records are as numerous as the records themselves and dictated by the information needs of the people conducting the search. Two very good uses that we are familiar with:
Finding historic photographs – very helpful to developers and homeowners when navigating historical preservation and zoning laws. In an instance we are familiar with a developer’s housing project was approved on land zoned as an agricultural preserve because the developer was able to produce photographic evidence that houses once stood on the property.
Locating unpublished manuscripts – extremely important when conducting a high-level vet. Because these writing were never formally published, their existence tends to be treated as more newsworthy than that of their published counterparts.