The Palazzo Imperiale was a brick- and reticulate-faced concrete structure which covered nearly three hectares. Of its original three storeys, only the substructures and some of the first floor remain. The Palazzo‘s trapezoidal plan was dictated by the spur of land between the two basins on which it was situated.
The structure has been of significant interest since the 16th century due to the discoveries of numerous columns, sculptures and inscriptions. The complex also contained its own bath suite in its southwest corner. The corpus of brickstamps found in the building indicates it was a predominantly Trajanic construction with later renovations undertaken by Hadrian and the Antonines. The building’s location as well as the evidence of its lavish marble decoration suggest it was presumably the headquarters of a high-ranking official or potentially the emperor himself.