The OSA Archive includes both digital and hard copy records. OSA maintains an in-house library with nearly 4,000 hardcopies of books, journals, videos, and maps. These are available to researchers and students to access at OSA during normal business hours.

Select documents are accessible through Iowa's Archaeological Research Center (iArc), an online database created by OSA. Over the past two decades, OSA has steadily worked on digitizing its paper documentation. Nearly 300,000 total records, including photographs, are digitized, and 94% are currently available digitally through iArc to OSA staff. Partial access to iArc is included with annual subscriptions to I-SitesPro, which is available to Secretary of the Interior qualified archaeologists.

Members of the public may also use portions of OSA's in-house archives, although OSA will withhold or redact sensitive and confidential site location information.