An integrated bypass channel and diverter assembly for hard disk drives having small form factors is disclosed. A bypass channel is formed directly in the base plate to allow a partial bypass to exist with or without a diverter feature. The design addresses the issue of proper disk shrouding at the same time as providing the desired features for small form factor drives. The invention includes three datum planes for aligning the machined features of the bypass channel with the drive during assembly. The machined bypass channel and the upstream diverter may be combined to form the integrated assembly. The primary air flow direction from the disk stack is through the integrated partial bypass in the enclosure body and around the diverter into the main bypass channel. The invention provides a drop-in position for the diverter that has minimal encroachment into the VCM area of the drive.