How do I launch a Git Bash window with particular working directory using a script?

Another option is to create a shortcut with the following properties:

Target should be:

"%SYSTEMDRIVE%\Program Files (x86)\Git\bin\sh.exe" --login

Start in is the folder you wish your Git Bash prompt to launch into.

Git Bash uses cmd.exe for its terminal plus extentions from MSYS/MinGW which are provided by sh.exe, a sort of cmd.exe wrapper. In Windows you launch a new terminal using the start command.

Thus a shell script which launches a new Git Bash terminal with a specific working directory is:

(cd C:/path/to/dir1 && start sh --login) &
(cd D:/path/to/dir2 && start sh --login) &

An equivalent Windows batch script is:

C:
cd \path\to\dir1
start "" "%SYSTEMDRIVE%\Program Files (x86)\Git\bin\sh.exe" --login 
D:
cd \path\to\dir2
start "" "%SYSTEMDRIVE%\Program Files (x86)\Git\bin\sh.exe" --login 

To get the same font and window size as the Git Bash launched from the start menu, it is easiest to copy the start menu shortcut settings to the command console defaults (to change defaults, open cmd.exe, left-click the upper left icon, and select Defaults).

Try the --cd= option. Assuming your GIT Bash resides in C:\Program Files\Git it would be:

"C:\Program Files\Git\git-bash.exe" --cd="e:\SomeFolder"

If used inside registry key, folder parameter can be provided with %1:

"C:\Program Files\Git\git-bash.exe" --cd="%1"