It is important to recognize and reduce the required spin-up time so that as much usable land surface model output as possible can be obtained from the retrospective simulation. Therefore, we have designed and undertaken numerical experiments to evaluate the production and evolution of model initial conditions (ICs) through model spin-up methods. Previous studies approached this issue by spinning up a model over a single recursive year of forcing or over multiple-year forcing climatology. We seek to build on these previous efforts by concentrating on an effort to increase spin-up efficiency as our research priority. Factors affecting the spin-up efficiency (forcing data, land surface type) will be fully evaluated in this study, and we expect to develop an effective and efficient spin-up strategy for obtaining an optimal initial condition and quantify the spin-up time needed for land surface modeling. This enhanced spin-up methodology will have broad applicability, with findings benefiting both operational and research-type simulations conducted at both OHD and EMC, as well as in the broader land-hydrology research community.