For most users, it is recommended to download the current stable release from https://cloud.r-project.org/.
Some developers might wish to use a different version, or to switch between versions. For this, the rvenv package can be useful.
R is also available for use in Brown's Computing Environments:
Oscar (for high-performance computing)
Stronghold (for secure computing)
Download and install the latest version of The R Project for Statistical computing for macOS here.
For an integrated development environment (IDE) / graphical interface, you can also download and install R Studio from here.