diff --git a/datasette/app.py b/datasette/app.py
index 3099ada7..c1c0663d 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -118,11 +118,6 @@ SETTINGS = (
         50,
         "Time limit for calculating a suggested facet",
     ),
-    Setting(
-        "hash_urls",
-        False,
-        "Include DB file contents hash in URLs, for far-future caching",
-    ),
     Setting(
         "allow_facet",
         True,
@@ -177,6 +172,16 @@ SETTINGS = (
     ),
     Setting("base_url", "/", "Datasette URLs should use this base path"),
 )
+OBSOLETE_SETTINGS = {
+    option.name: option
+    for option in (
+        Setting(
+            "hash_urls",
+            False,
+            "The hash_urls setting has been removed, try the datasette-hashed-urls plugin instead",
+        ),
+    )
+}
 
 DEFAULT_SETTINGS = {option.name: option.default for option in SETTINGS}
 
diff --git a/datasette/cli.py b/datasette/cli.py
index 61e7ce91..b94ac192 100644
--- a/datasette/cli.py
+++ b/datasette/cli.py
@@ -12,7 +12,14 @@ from subprocess import call
 import sys
 from runpy import run_module
 import webbrowser
-from .app import Datasette, DEFAULT_SETTINGS, SETTINGS, SQLITE_LIMIT_ATTACHED, pm
+from .app import (
+    OBSOLETE_SETTINGS,
+    Datasette,
+    DEFAULT_SETTINGS,
+    SETTINGS,
+    SQLITE_LIMIT_ATTACHED,
+    pm,
+)
 from .utils import (
     StartupError,
     check_connection,
@@ -50,8 +57,12 @@ class Config(click.ParamType):
             return
         name, value = config.split(":", 1)
         if name not in DEFAULT_SETTINGS:
+            if name in OBSOLETE_SETTINGS:
+                msg = OBSOLETE_SETTINGS[name].help
+            else:
+                msg = f"{name} is not a valid option (--help-settings to see all)"
             self.fail(
-                f"{name} is not a valid option (--help-settings to see all)",
+                msg,
                 param,
                 ctx,
             )
@@ -83,8 +94,12 @@ class Setting(CompositeParamType):
     def convert(self, config, param, ctx):
         name, value = config
         if name not in DEFAULT_SETTINGS:
+            if name in OBSOLETE_SETTINGS:
+                msg = OBSOLETE_SETTINGS[name].help
+            else:
+                msg = f"{name} is not a valid option (--help-settings to see all)"
             self.fail(
-                f"{name} is not a valid option (--help-settings to see all)",
+                msg,
                 param,
                 ctx,
             )
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 5afe72c1..89e8d044 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -310,3 +310,10 @@ def test_help_settings():
     result = runner.invoke(cli, ["--help-settings"])
     for setting in SETTINGS:
         assert setting.name in result.output
+
+
+def test_help_error_on_hash_urls_setting():
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--setting", "hash_urls", 1])
+    assert result.exit_code == 2
+    assert 'The hash_urls setting has been removed' in result.output