GADM wants to map the administrative areas of all countries, at all levels of sub-division. GADM provides maps and spatial data for all countries and their sub-divisions for download from its website. This package facilitates access to these maps and spatial data for download in R.
You can install the development version of gadmr from
GitHub with:
if(!require(remotes)) install.packages("remotes")
if(!require(gadmr)) remotes::install_github("SpatialWorks/gadmr")