Dear Folks,
Recently, on a climb I met a prominent user of this list who was not aware of GPSFileDepot, so I thought perhaps others might not be either...
GPSFileDepot, https://www.gpsfiledepot.com/, is a repository of GPS maps, including excellent free topo maps of every US state. You can download and install the maps to your PC, and then open them in Garmin's BaseCamp software. BaseCamp includes a map installer that allows you to transfer the maps to your Garmin GPS unit.
Some of the best free maps are tagged "Editor's Choice," see this link: https://www.gpsfiledepot.com/maps/search/editorschoice/. This is where you find the excellent free topo maps I mentioned above.
Unfortunately, it just so happens that the current Window's version of BaseCamp software, version 4.7.0, has a bug in its MapInstaller, so it won't install maps to your Garmin. Hence, if you wish to install maps from GPSFileDepot, don't upgrade to version 4.7.0 of BaseCamp - keep the one you have. If you already upgraded to version 4.7.0, uninstall it using the Window's control panel, and then install the previous version, v.4.6.2, (BaseCamp_462.exe) which is available here: http://www.gawisp.com/perry/mapsource/.
Lars.