If you want to uninstall MacPorts and the port command is functioning, first uninstall all the installed ports by running this command in the Terminal:

$ sudo port -fp uninstall installed

All that will be left in your installation prefix now will be files that were not registered to any port. This includes configuration files, databases, any files which MacPorts renamed in order to allow a forced installation or upgrade, and the base MacPorts software itself. You may wish to save your configuration files (most are in $prefix/etc), databases, or any other unique data by moving it aside.

If the port command is not functioning, you can proceed on to the next steps, but if you had installed any ports that install files to nonstandard locations, those files might not be removed.

When MacPorts is installed, a macports macOS user and group are created for privilege separation. If you want to remove them, you can use these commands from an account that has admin privileges:

$ sudo dscl . -delete /Users/macports
$ sudo dscl . -delete /Groups/macports

If you configured MacPorts to use a different user or group name, then specify that instead of macports.

Individual ports may create users and groups as well; you can remove them with the same commands, but replacing macports with the user or group name you wish to delete.

If you want to remove all remaining traces of MacPorts, run the following command in the Terminal. If you have changed prefix, applications_dir or frameworks_dir from their default values, then replace /opt/local with your prefix, replace /Applications/MacPorts with your applications_dir, and/or add your frameworks_dir to the list, respectively.

If you are running macOS 10.15 Catalina or later and have not disabled System Integrity Protection (SIP), you will need to remove the macports user first.

$ sudo rm -rf \
    /opt/local \
    /Applications/DarwinPorts \
    /Applications/MacPorts \
    /Library/LaunchDaemons/org.macports.* \
    /Library/Receipts/DarwinPorts*.pkg \
    /Library/Receipts/MacPorts*.pkg \
    /Library/StartupItems/DarwinPortsStartup \
    /Library/Tcl/darwinports1.0 \
    /Library/Tcl/macports1.0 \
    ~/.macports

If you use a shell other than bash (perhaps tcsh), you may need to adjust the above to fit your shell's syntax.

Depending on which version of MacPorts you have and which ports you have installed, not all of the above paths will exist on your system; this is OK.