In integrated airframe/propulsion system configurations, additional noise sources can be created from the interactions between the jet flow and the adjacent airframe surfaces. Another situation of surfaces of close proximity occur during takeoff and landing when the ground is close enough to cause the jet-surface interference. The impact of a plate oriented parallel to the axis of a 2:1 rectangular supersonic jet (De = 20.65mm) at the minor axis side is studied. Plate offset (h) distances of h = 0, 1, 2, and 3 equivalent diameters from the nozzle lip to the surface are included. The impact of the plate is studied at nozzle pressure ratios (NPRs) of 2.5–4.5 when the design Mach number is 3.67, at a temperature ratio of TR = 1.1. Mean and turbulent flow field data are acquired using streamwise particle image velocimetry (PIV). Trends of shock cell spacing, potential core length, and shear layer development are analyzed. Near and far field data are taken and correlated with the flow field details. The offset from the nozzle is shown to vary flow and acoustic properties and impact screech tones.