In critical state soil mechanics, the critical state refers to the combination of effective stress and void ratio at which a soil continues to shear with no change in effective stress, shear stress, and void ratio. The phenomena can be visualized using the critical state line (CSL). The CSL represents the locus of void ratio at critical state with effective mean stress. To define the CSL, the CSL slope, termed “compressibility,” and CSL y-axis intercept at 1 kPa, termed “altitude,” are required. The CSL in void ratio – effective mean stress space provides a simple model of complex soil behavior that allows engineers to construct constitutive models using the state parameter, which is the mathematical difference between the in-situ void ratio of the soil and the void ratio of the soil at critical state. Currently, altitude can be obtained only through laboratory testing, while compressibility and state parameter can be obtained via laboratory testing or correlation. This paper presents forthcoming correlations based on the ΔQ soil behavior index (which is obtained via the cone penetration test, CPT) to forecast altitude, compressibility, and state parameter, and compares the ΔQ-based correlations’ performance to other CPT-based correlations as well as to data obtained from literature. To compare the correlations, the authors used data from a site investigation performed in Fraser River sand as part of the Canadian Liquefaction Experiment.