Leveling and precise gravity observations were made along a 50-km profile before and after the filling of the La Grande-2 reservoir (53.7¿N, 77¿W) in 1979. Anomalous relative vertical uplift of 4 cm and relative changes in gravity of 14 μGal (140 nm/s2) were observed along the profile. The observed changes are anomalous with respect to theoretical results for loading of a layered elastic earth. Homogeneous, isotropic, porous, elastic models with reasonable hydraulic properties are also unable to explain the observations. In an effort to account for the discrepancies the accuracies of the leveling and the gravity data were investigated. Corrections were made to the leveling data for refraction errors, rod calibrations, magnetic effects, and deflection of the vertical by the water mass. Although the corrections for systematic errors were significant, the discrepancy with respect to homogeneous, isotropic loading models remains. The anomalous increase in gravity is thought to be the result of lateral transport of water in ∂ high-permeability formerly undersaturated zone, hydraulically coupled to the reservoir. The anomalous uplift is thought to be the result of elastic expansion of cracks and fractures of low aspect ratio in the high-permeability zone or the result of an unexpectedly high rate of regional tilting in the LaGrande-2 area.