Residual shear tests were conducted on samples from near the failure surfaces. Strength parameters varied depending on the way the sample was prepared and tested. Minimum values were obtained in a ring shear device on samples that had the coarse fractions removed. A reasonable estimate of the residual strength parameters is an angle of internal friction of 16 degrees with a small cohesion intercept of 10 kPa. Other typical properties of the colluvium are LL=45, PI=22, sand =10 percent, silt = 30 percent, and clay = 60 percent. The clay minerals are predominantly illite and mixed layer clay. Stability analyses conducted by back-calculation gave expectable results for the thick landslides. At equilibrium, our measured values of residual strength are adequate to support the slope for the geometry and water conditions observed. For the thin landslides, the measured strength appears insufficient to support the slope. Additional strength provided by tree roots, roughness of the failure surface, or small residual cohesion could account for the discrepancy between apparent strength and stability.