gcamland v1.0 is an open source R package that was built to allocate land across a variety of uses based on changes in agricultural yield and commodity price. The land allocation algorithm is based on the one included in the Global Change Assessment Model (GCAM). gcamland v1.0 includes the ability to run in a historical mode, enabling model validation and parameter estimation, or in a future mode, simulating changes in land use/land cover in the future. For both modes, gcamland v1.0 can run a single simulation or a large ensemble of simulations with different parameters. When ensembles are generated in the historical mode, gcamland v1.0 calculates the likelihood of a given parameter set by comparing to observational data. gcamland v1.0 is publicly available via GitHub and has can be adjusted to represent alternative scenarios or configured to different regions and land types.