diff --git a/USAGE.md b/USAGE.md
index 7b684782d..9e766be02 100644
--- a/USAGE.md
+++ b/USAGE.md
@@ -68,16 +68,36 @@ This will both uninstall and unlink the Cask.
 
 ## Options
 
-You can set options on the command-line and/or using the `HOMEBREW_CASK_OPTS` environment variable, e.g. (again, using google-chrome):
+You can provide a number of options to the `brew cask` command to modify the default
+installation locations.
+
+* `--caskroom=/my/path` determines where the actual applications will be located.
+Default is `/opt/homebrew-cask/Caskroom`
+* `--appdir=/my/path` changes the path where the symlinks to the applications (above)
+will be generated. This is commonly used to create the links in the _root_ Applications directory
+instead of the _home_ Applications directory by specifying `--appdir=/Applications`. Default is `~/Applications`.
+* `--prefpanedir=/my/path` changes the path for PreferencePane symlinks.
+Default is `~/Library/PreferencePanes`
+* `--qlplugindir=/my/path` changes the path for Quicklook Plugin symlinks.
+Default is `~/Library/QuickLook`
+* `--widgetdir=/my/path` changes the path for Dashboard Widget symlinks.
+Default is `~/Library/Widgets`
+* `--fontdir=/my/path` changes the path for Fonts symlinks.
+Default is `~/Library/Fonts`
+
+To make these changes permanent, you might want to add the following line to your `.bash_profile` or `.zshenv`:
 
 ```bash
-# This probably should happen in your ~/.{ba|z}shrc
-$ export HOMEBREW_CASK_OPTS="--appdir=/Applications"
+# Specify your defaults in this environment variable
+export HOMEBREW_CASK_OPTS="--appdir=/Applications --caskroom=/etc/Caskroom"
+```
 
-# Installs app links to /Applications
-$ brew cask install google-chrome
+Note that you still can override the environment variable `HOMEBREW_CASK_OPTS` by _explicitly_ providing
+the options in the command line:
 
-# Trumps the ENV and installs app links to ~/Applications
+```bash
+# Will force the Chrome app to be linked to ~/Applications
+# even though HOMEBREW_CASK_OPTS specified /Applications
 $ brew cask install --appdir="~/Applications" google-chrome
 ```
 
diff --git a/lib/cask/cli.rb b/lib/cask/cli.rb
index 41329db8f..efa43ab78 100644
--- a/lib/cask/cli.rb
+++ b/lib/cask/cli.rb
@@ -58,7 +58,11 @@ class Cask::CLI
   end
 
   def self.parser
+    # If you modify these arguments, please update USAGE.md
     @parser ||= OptionParser.new do |opts|
+      opts.on("--caskroom=MANDATORY") do |v|
+        Cask.caskroom = Pathname(v).expand_path
+      end
       opts.on("--appdir=MANDATORY") do |v|
         Cask.appdir = Pathname(v).expand_path
       end
diff --git a/test/cask/cli_test.rb b/test/cask/cli_test.rb
index a67210d2d..eb4b6524f 100644
--- a/test/cask/cli_test.rb
+++ b/test/cask/cli_test.rb
@@ -74,6 +74,28 @@ describe Cask::CLI do
       custom_qlplugin_dir.directory?.must_equal true
     end
 
+    it "respects the ENV variable when choosing a non-default Caskroom location" do
+      default_caskroom_dir = Cask.caskroom
+      default_caskroom_dir.rmdir
+      custom_caskroom_dir = Pathname(Dir.mktmpdir('custom_caskroom_dir'))
+      custom_caskroom_dir.rmdir
+
+      default_caskroom_dir.directory?.must_equal false
+      custom_caskroom_dir.directory?.must_equal false
+
+      begin
+        ENV['HOMEBREW_CASK_OPTS'] = "--caskroom=#{custom_caskroom_dir}"
+        shutup {
+          Cask::CLI.process('list')
+        }
+      ensure
+        ENV.delete 'HOMEBREW_CASK_OPTS'
+      end
+
+      default_caskroom_dir.directory?.must_equal false
+      custom_caskroom_dir.directory?.must_equal true
+    end
+
     it "exits with a status of 1 when something goes wrong" do
       Cask::CLI.expects(:exit).with(1)
       Cask::CLI.expects(:lookup_command).raises(CaskError)