Vertical Disk Structure in HL Tauri

New J, H, and K' images of HL Tau show that the position of the peak intensity shifts by 053 ± 007 along P.A. 75° ± 8° between 2.12 μm (K') and 1.25 μm (J). There is a strong gradient in the color of the extended light around in the same direction. This direction is coincident with the axis of the optical emission jet and the axis of the circumstellar disk inferred from millimeter-wave maps. It is likely that the star itself is viewed through more than 30 mag of visual extinction and is only seen directly at wavelengths longer than about 1.6 μm; the distribution of light at J is more diffuse, and the peak is probably the result of viewing an extended region of scattered light behind a gradient of extinction. The projected scale height of the extinction gradient is less than a few tens of AU along a direction nearly perpendicular to the disk, indicating that the extinction gradient is local to HL Tau, within a few hundred AU of the star. The distribution and color of the extended light suggest that it is scattered by an extended, conical nebula surrounding the star associated with the molecular infall observed in ¹³CO.