This paper models the supply curve of carbon sequestration on Pacific Northwest rangelands. Rangeland managers have the ability to sequester carbon in agricultural soils by implementing alternative management practices on their farms. Their low adoption rate in practice suggests a high opportunity cost associated with their implementation. To increase their adoption, a payment for ecosystem services plan is proposed, where the public compensates farms for lost profits. The TOA-MD model is used to estimate the resulting sequestration incentivized by payments for soil carbon sequestration. Methodological questions of geographical stratification and estimating variation from available data are tested. Sensitivity analysis is also run on key assumptions in the study. Results show that while the economic potential of both systems is much lower than the technical potential, at reasonable CO₂ payment levels rangeland sequestration could be a significant mitigation strategy for Pacific Northwest states.