Thermal conductivities were determined for 10 fine-grained soils obtained from potential borrow pit areas along the proposed route of the Mackenzie Highway, N.W.T., and from the nearly completed section of the Mackenzie Highway, just south of Inuvik. The moisture contents and densities of the test specimens were based on the standard Proctor density curves. The measurements were made by the transient heat-flow method using a line heat source. The values were in good agreement with Kersten's data obtained by the steady-state heat flow method.Grain-size, mineralogical analyses of the clay-size fraction, Atterberg limits, and standard Proctor density determinations are given for all 10 soils.