We analyzed U.S. Department of the Interior (DOI) transaction data for the first 6 months of fiscal year 2017 to determine whether (1) the DOI or its bureaus made transactions that were illegal, improper, or erroneous and (2) the existing internal controls detected and prevented illegal, improper, or erroneous transactions. We conducted this audit as part of a Governmentwide initiative by the Council of the Inspectors General on Integrity and Efficiency to examine risks associated with U.S.