Gramps 4.0 Wiki Manual - User Directory
The location of your GRAMPS user directory depends on the operating system you are using and how you have set up your computer. In the table below <~username> should be replaced by the name you use to log in to your computer.
The default location for an installation of GRAMPS in a POSIX-style environment is:
On Macs, filenames starting with "." do not show up in Finder. To make access to the Gramps user directory easy, open a terminal window with Finder-Applications-Utilities-Terminal and type there
ln -s .gramps gramps_user_directory
which will allow Finder to show the contents.
The default location for an installation on a Windows system is
C:\Documents and Settings\<~username>\Application Data\gramps