Stores downloaded NuGet packages (.nupkg).
~/.local/share/NuGet/Cache ~/.nuget/packages
%LocalAppData%\NuGet\Cache %UserProfile%.nuget\packages
The NuGet.Config file stores user defined NuGet package sources, credentials and proxy settings. The default location for this file is:
~/.config/NuGet/NuGet.Config
%AppData%\NuGet\NuGet.Config
Machine wide configurations are used to define NuGet package sources specific to a machine or a particular IDE, such as Visual Studio.
Mac
Windows %ProgramData%\NuGet\Config
(credit from Matt Ward's blog http://lastexitcode.com/projects/NuGet/FileLocations/)