diff --git a/docs/index.rst b/docs/index.rst
index bb58db3..dca92e0 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -24,7 +24,7 @@ unpack those dependencies to a known location, add them to your interpreter's se
 .. note::
     "Conventional" zipapps don't include any dependencies, which is what sets shiv apart from the stdlib zipapp module.
 
-shiv accepts only a few command line parameters of its own, `described here <cli-reference>`_, and any unprocessed parameters are
+shiv accepts only a few command line parameters of its own, `described here <cli-reference.html>`_, and any unprocessed parameters are
 delegated to ``pip install``. This allows users to fully leverage all the functionality that pip provides.
 
 For example, if you wanted to create an executable for ``flake8``, you'd specify the required
@@ -94,7 +94,7 @@ Influencing Runtime
 -------------------
 
 Whenever you are creating a zipapp with ``shiv``, you can specify a few flags that influence the runtime.
-For example, the `-c/--console-script` and `-e/--entry-point` options already mentioned in this doc.
+For example, the ``-c/--console-script`` and ``-e/--entry-point`` options already mentioned in this doc.
 To see the full list of command line options, see this page.
 
 In addition to options that are settable during zipapp creation, there are a number of environment variables
@@ -117,7 +117,7 @@ dropping into an interactive session in the environment of a built cli utility.
 SHIV_ENTRY_POINT
 ^^^^^^^^^^^^^^^^
 
-.. note:: Same functionality as "-e/--entry-point" at build time
+.. note:: Same functionality as ``-e/--entry-point`` at build time
 
 This should be populated with a setuptools-style callable, e.g. "module.main:main". This will
 execute the pyz with whatever callable entry point you supply. Useful for sharing a single pyz
@@ -132,7 +132,7 @@ hotfixes/modifications to the 'cached' dependencies, this will overwrite them.
 SHIV_EXTEND_PYTHONPATH
 ^^^^^^^^^^^^^^^^^^^^^^
 
-.. note:: Same functionality as "-E/--extend-pythonpath" at build time.
+.. note:: Same functionality as ``-E/--extend-pythonpath`` at build time.
 
 This is a boolean that adds the modules bundled into the zipapp into the ``PYTHONPATH`` environment
 variable. It is not needed for most applications, but if an application calls Python as a
diff --git a/src/shiv/bootstrap/__init__.py b/src/shiv/bootstrap/__init__.py
index 46a0454..708ab05 100644
--- a/src/shiv/bootstrap/__init__.py
+++ b/src/shiv/bootstrap/__init__.py
@@ -89,9 +89,17 @@ def cache_path(archive, root_dir, build_id):
     """Returns a ~/.shiv cache directory for unzipping site-packages during bootstrap.
 
     :param ZipFile archive: The zipfile object we are bootstrapping from.
-    :param Path root_dir: Optional, the path to a SHIV_ROOT.
+    :param str root_dir: Optional, either a path or environment variable pointing to a SHIV_ROOT.
     :param str build_id: The build id generated at zip creation.
     """
+
+    if root_dir:
+
+        if root_dir.startswith("$"):
+            root_dir = os.environ.get(root_dir[1:], root_dir[1:])
+
+        root_dir = Path(root_dir)
+
     root = root_dir or Path("~/.shiv").expanduser()
     name = Path(archive.filename).resolve().stem
     return root / f"{name}_{build_id}"
diff --git a/src/shiv/bootstrap/environment.py b/src/shiv/bootstrap/environment.py
index 1f7c6f0..9cce42e 100644
--- a/src/shiv/bootstrap/environment.py
+++ b/src/shiv/bootstrap/environment.py
@@ -5,8 +5,6 @@ overrides defined at runtime (via environment variables).
 import json
 import os
 
-from pathlib import Path
-
 
 def str_bool(v):
     if not isinstance(v, bool):
@@ -38,6 +36,7 @@ class Environment:
         reproducible=False,
         script=None,
         preamble=None,
+        root=None,
     ):
         self.always_write_cache = always_write_cache
         self.build_id = build_id
@@ -53,6 +52,7 @@ class Environment:
         self._entry_point = entry_point
         self._compile_pyc = compile_pyc
         self._extend_pythonpath = extend_pythonpath
+        self._root = root
 
     @classmethod
     def from_json(cls, json_data):
@@ -74,8 +74,8 @@ class Environment:
 
     @property
     def root(self):
-        root = os.environ.get(self.ROOT)
-        return Path(root) if root is not None else None
+        root = os.environ.get(self.ROOT, self._root)
+        return root
 
     @property
     def force_extract(self):
diff --git a/src/shiv/cli.py b/src/shiv/cli.py
index 8273395..f92f0ef 100644
--- a/src/shiv/cli.py
+++ b/src/shiv/cli.py
@@ -168,6 +168,7 @@ def copytree(src: Path, dst: Path) -> None:
         "but before invoking your entry point."
     ),
 )
+@click.option("--root", type=click.Path(), help="Override the 'root' path (default is ~/.shiv).")
 @click.argument("pip_args", nargs=-1, type=click.UNPROCESSED)
 def main(
     output_file: str,
@@ -181,6 +182,7 @@ def main(
     reproducible: bool,
     no_modify: bool,
     preamble: Optional[str],
+    root: Optional[str],
     pip_args: List[str],
 ) -> None:
     """
@@ -258,6 +260,7 @@ def main(
             no_modify=no_modify,
             reproducible=reproducible,
             preamble=Path(preamble).name if preamble else None,
+            root=root,
         )
 
         if no_modify:
diff --git a/src/shiv/constants.py b/src/shiv/constants.py
index f126101..36fee4f 100644
--- a/src/shiv/constants.py
+++ b/src/shiv/constants.py
@@ -17,7 +17,7 @@ DISALLOWED_ARGS: Dict[Tuple[str, ...], str] = {
         "--editable",
     ): "Editable installs don't actually install via pip (they are just linked), so they are not allowed.",
     ("-d", "--download"): "Shiv needs to actually perform an install, not merely a download.",
-    ("--user", "--root", "--prefix"): "Which conflicts with Shiv's internal use of '--target'.",
+    ("--user", "--prefix"): "Which conflicts with Shiv's internal use of '--target'.",
 }
 
 SOURCE_DATE_EPOCH_ENV = "SOURCE_DATE_EPOCH"

diff --git a/test/conftest.py b/test/conftest.py
index c79dd0f..7a68895 100644
--- a/test/conftest.py
+++ b/test/conftest.py
@@ -1,3 +1,6 @@
+import os
+
+from contextlib import contextmanager
 from pathlib import Path
 
 import pytest
@@ -31,3 +34,15 @@ def env():
         extend_pythonpath=False,
         shiv_version="0.0.1",
     )
+
+
+@pytest.fixture
+def env_var():
+
+    @contextmanager
+    def _env_var(key, value):
+        os.environ[key] = value
+        yield
+        del os.environ[key]
+
+    return _env_var
diff --git a/test/test_bootstrap.py b/test/test_bootstrap.py
index 6fb5111..54df208 100644
--- a/test/test_bootstrap.py
+++ b/test/test_bootstrap.py
@@ -2,7 +2,6 @@ import os
 import sys
 
 from code import interact
-from contextlib import contextmanager
 from datetime import datetime
 from pathlib import Path
 from site import addsitedir
@@ -26,13 +25,6 @@ from shiv.bootstrap.filelock import FileLock
 from shiv.pip import install
 
 
-@contextmanager
-def env_var(key, value):
-    os.environ[key] = value
-    yield
-    del os.environ[key]
-
-
 class TestBootstrap:
     def test_import_string(self):
         assert import_string("site.addsitedir") == addsitedir
@@ -68,12 +60,15 @@ class TestBootstrap:
         with current_zipfile() as zipfile:
             assert not zipfile
 
-    def test_cache_path(self):
+    def test_cache_path(self, env_var):
         mock_zip = mock.MagicMock(spec=ZipFile)
         mock_zip.filename = "test"
         uuid = str(uuid4())
 
-        assert cache_path(mock_zip, Path.cwd(), uuid) == Path.cwd() / f"test_{uuid}"
+        assert cache_path(mock_zip, 'foo', uuid) == Path("foo", f"test_{uuid}")
+
+        with env_var("FOO", "foo"):
+            assert cache_path(mock_zip, '$FOO', uuid) == Path("foo", f"test_{uuid}")
 
     def test_first_sitedir_index(self):
         with mock.patch.object(sys, "path", ["site-packages", "dir", "dir", "dir"]):
@@ -124,7 +119,7 @@ class TestBootstrap:
 
 
 class TestEnvironment:
-    def test_overrides(self):
+    def test_overrides(self, env_var):
         now = str(datetime.now())
         version = "0.0.1"
         env = Environment(now, version)
@@ -142,7 +137,7 @@ class TestEnvironment:
 
         assert env.root is None
         with env_var("SHIV_ROOT", "tmp"):
-            assert env.root == Path("tmp")
+            assert env.root == "tmp"
 
         assert env.force_extract is False
         with env_var("SHIV_FORCE_EXTRACT", "1"):
diff --git a/test/test_cli.py b/test/test_cli.py
index 662a1ce..b5acf08 100644
--- a/test/test_cli.py
+++ b/test/test_cli.py
@@ -346,3 +346,54 @@ class TestCLI:
 
         assert proc.returncode == 0
         assert proc.stdout.decode().splitlines() == ["hello from preamble", "hello world"]
+
+    def test_alternate_root(self, runner, package_location, tmp_path):
+        """Test that the --root argument properly sets the extraction root."""
+
+        output_file = tmp_path / "test.pyz"
+        shiv_root = tmp_path / "root"
+        result = runner(
+            ["-e", "hello:main", "--root", str(shiv_root), "-o", str(output_file), str(package_location)]
+        )
+
+        # check that the command successfully completed
+        assert result.exit_code == 0
+
+        # ensure the created file actually exists
+        assert output_file.exists()
+
+        # now run the produced zipapp
+        proc = subprocess.run(
+            [str(output_file)], stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, env=os.environ,
+        )
+
+        assert proc.returncode == 0
+        assert "hello" in proc.stdout.decode()
+        assert shiv_root.exists()
+
+    def test_alternate_root_environment_variable(self, runner, package_location, tmp_path, env_var):
+        """Test that the --root argument works with environment variables."""
+
+        output_file = tmp_path / "test.pyz"
+        shiv_root_var = "NEW_ROOT"
+        shiv_root_path = tmp_path / 'new_root'
+        result = runner(
+            ["-e", "hello:main", "--root", "$" + shiv_root_var, "-o", str(output_file), str(package_location)]
+        )
+
+        with env_var(shiv_root_var, str(shiv_root_path)):
+
+            # check that the command successfully completed
+            assert result.exit_code == 0
+
+            # ensure the created file actually exists
+            assert output_file.exists()
+
+            # now run the produced zipapp
+            proc = subprocess.run(
+                [str(output_file)], stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, env=os.environ,
+            )
+
+        assert proc.returncode == 0
+        assert "hello" in proc.stdout.decode()
+        assert shiv_root_path.exists()

Set default $SHIV_HOME as CWD while packaging?
Is there a way to set the default SHIV_HOME path with current work dir?

These days I used app.pyz which packaged with shiv and raised an error for missing the HOME path on hadoop data nodes.

So could I set the default shiv cache folder path as ./_shiv_cache instead of ~/.shiv, without any environment variable?

test/test_bootstrap.py::TestBootstrap::test_cache_path test/test_bootstrap.py::TestEnvironment::test_overrides test/test_cli.py::TestCLI::test_alternate_root test/test_cli.py::TestCLI::test_alternate_root_environment_variable
test/test_bootstrap.py::TestBootstrap::test_import_string test/test_bootstrap.py::TestBootstrap::test_is_zipfile test/test_bootstrap.py::TestBootstrap::test_argv0_is_not_zipfile test/test_bootstrap.py::TestBootstrap::test_first_sitedir_index test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[False-False-False] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[False-False-True] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[False-True-False] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[False-True-True] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[True-False-False] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[True-False-True] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[True-True-False] test/test_bootstrap.py::TestBootstrap::test_extract_site_packages[True-True-True] test/test_bootstrap.py::TestBootstrap::test_extend_path[additional_paths0] test/test_bootstrap.py::TestBootstrap::test_extend_path[additional_paths1] test/test_bootstrap.py::TestBootstrap::test_extend_path_existing_pythonpath test/test_bootstrap.py::TestEnvironment::test_roundtrip test/test_bootstrap.py::TestEnvironment::test_lock test/test_bootstrap.py::TestEnvironment::test_ensure_no_modify test/test_cli.py::TestCLI::test_find_entry_point test/test_cli.py::TestCLI::test_find_entry_point_two_points test/test_cli.py::TestCLI::test_console_script_exists test/test_cli.py::TestCLI::test_no_args test/test_cli.py::TestCLI::test_no_outfile test/test_cli.py::TestCLI::test_find_interpreter test/test_cli.py::TestCLI::test_find_interpreter_false test/test_cli.py::TestCLI::test_disallowed_args[-t] test/test_cli.py::TestCLI::test_disallowed_args[--target] test/test_cli.py::TestCLI::test_disallowed_args[--editable] test/test_cli.py::TestCLI::test_disallowed_args[-d] test/test_cli.py::TestCLI::test_disallowed_args[--download] test/test_cli.py::TestCLI::test_disallowed_args[--user] test/test_cli.py::TestCLI::test_disallowed_args[--prefix] test/test_cli.py::TestCLI::test_hello_world[yes-compile_option0] test/test_cli.py::TestCLI::test_hello_world[yes-compile_option1] test/test_cli.py::TestCLI::test_hello_world[no-compile_option0] test/test_cli.py::TestCLI::test_hello_world[no-compile_option1] test/test_cli.py::TestCLI::test_extend_pythonpath[extend_path0] test/test_cli.py::TestCLI::test_extend_pythonpath[extend_path1] test/test_cli.py::TestCLI::test_extend_pythonpath[extend_path2] test/test_cli.py::TestCLI::test_multiple_site_packages test/test_cli.py::TestCLI::test_no_entrypoint test/test_cli.py::TestCLI::test_results_are_binary_identical_with_env_and_build_id test/test_cli.py::TestCLI::test_preamble[preamble.py-#!/usr/bin/env test/test_cli.py::TestCLI::test_preamble[preamble.sh-#!/bin/sh\necho test/test_cli.py::TestCLI::test_preamble_no_pip