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Current best practices for the assessment of the cyclic response of plastic silts are centered on the careful sampling and cyclic testing of natural, intact specimens. Side-by-side evaluation of in-situ and laboratory element test responses are severely limited, despite the need to establish similarities and differences in their characteristics. In this paper, a coordinated laboratory and field-testing campaign that was undertaken to compare the strain-controlled cyclic response of a plastic silt deposit at the Port of Longview, Longview, WA is described. Following a discussion of the subsurface conditions at one of several test panels, the responses of laboratory test specimens to resonant column and cyclic torsional shear testing, and constant-volume, strain-controlled cyclic direct simple shear testing are described in terms of shear modulus nonlinearity and degradation, and excess pore pressure generation with shear strain. Several months earlier, the in-situ cyclic response of the same deposit was investigated by applying a range of shear strain amplitudes using a large mobile shaker. The in-situ response is presented and compared to the laboratory test results, highlighting similarities and differences arising from differences in mechanical (e.g., constant-volume shearing; strain rate-effects) and hydraulic (e.g., local drainage) boundary conditions and the spatial variability of natural soil deposits.