rFIA is an R package designed to simplify the estimation of forest variables using the Forest Inventory and Analysis (FIA) Database and unlock the flexibility inherent to the Enhanced FIA design. rFIA was designed to improve accessibility to the spatio-temporal estimation capacity of the FIA Database via space-time indexed summaries of forest variables within user-defined population boundaries, in a widely used, open-source programming language. With direct integration with other popular R packages (e.g., dplyr, sp, and sf), rFIA facilitates efficient space-time query and data summary, and supports common data representations and API design. The package implements design-based estimation procedures outlined by Bechtold & Patterson (2005), and has been validated against estimates and sampling errors produced by EVALIDator. Current development is focused on the implementation of spatially-enabled model-assisted estimators to improve population, change, and ratio estimates.