The J_R-curves associated with small crack growth in 0.8-mm-thick 2024-T3, 2024-0, 5052-H32 aluminum and 2091-T3 aluminum-lithium cruciform specimens and 2024-T3 and 2024-0 aluminum single-edge-notched (SEN) specimens are presented. The cruciform specimens were loaded uniaxially and biaxially. The J-integral values were determined directly through contour integration of the stresses and strains using deformation theory of plasticity and power hardening law. The strains were computed from the measured in-plane displacements that were determined experimentally using moiré interferometry. Path independency of the J-integral values were verified by the 5% scatter band for the near- and far-field Js. The J_R results differed substantially from the J-values computed by using the far-field formula of Shih, German, and Kumar. Also the measured crack-tip displacement and strain fields did not agree with the asymptotic solutions of Hutchinson, Rice, and Rosengren computed from the measured J-values. These findings suggest that the current formulas for J calculations may be incorrect and that J may not be a suitable parameter for characterizing the crack tip.