diff --git a/csp/conf/__init__.py b/csp/conf/__init__.py
index aaf64c8..c407682 100644
--- a/csp/conf/__init__.py
+++ b/csp/conf/__init__.py
@@ -1,26 +1,57 @@
-from . import defaults
-
-
-DIRECTIVES = set(defaults.POLICY)
-PSEUDO_DIRECTIVES = {d for d in DIRECTIVES if '_' in d}
-
-
-def setting_to_directive(setting, value, prefix='CSP_'):
-    setting = setting[len(prefix):].lower()
-    if setting not in PSEUDO_DIRECTIVES:
-        setting = setting.replace('_', '-')
-    assert setting in DIRECTIVES
-    if isinstance(value, str):
-        value = [value]
-    return setting, value
+__all__ = [
+    'defaults',
+    'deprecation',
+    'directive_to_setting',
+    'get_declared_policies',
+    'get_declared_policy_definitions',
+    'setting_to_directive',
+    'DIRECTIVES',
+]
+
+from django.conf import settings
 
-
-def directive_to_setting(directive, prefix='CSP_'):
-    setting = '{}{}'.format(
-        prefix,
-        directive.replace('-', '_').upper()
+from . import defaults
+from .deprecation import (
+    directive_to_setting,
+    setting_to_directive,
+    _handle_legacy_settings,
+)
+
+
+DIRECTIVES = defaults.DIRECTIVES
+PSEUDO_DIRECTIVES = defaults.PSEUDO_DIRECTIVES
+
+
+def _csp_definitions_update(csp_definitions, other):
+    """ Update one csp definitions dictionary with another """
+    if isinstance(other, dict):
+        other = other.items()
+    for name, csp in other:
+        csp_definitions.setdefault(name, {}).update(csp)
+    return csp_definitions
+
+
+def get_declared_policy_definitions():
+    custom_definitions = _csp_definitions_update(
+        {},
+        getattr(
+            settings,
+            'CSP_POLICY_DEFINITIONS',
+            {'default': {}},
+        ),
+    )
+    _handle_legacy_settings(
+        custom_definitions['default'],
+        allow_legacy=not hasattr(settings, 'CSP_POLICY_DEFINITIONS'),
+    )
+    definitions = _csp_definitions_update(
+        {},
+        {name: defaults.POLICY for name in custom_definitions}
     )
-    return setting
+    for name, csp in custom_definitions.items():
+        definitions.setdefault(name, {}).update(csp)
+    return definitions
 
 
-LEGACY_KWARGS = {directive_to_setting(d, prefix='') for d in DIRECTIVES}
+def get_declared_policies():
+    return getattr(settings, 'CSP_POLICIES', defaults.POLICIES)
diff --git a/csp/conf/defaults.py b/csp/conf/defaults.py
index e47437b..b918ecb 100644
--- a/csp/conf/defaults.py
+++ b/csp/conf/defaults.py
@@ -42,3 +42,6 @@
     'include_nonce_in': ('default-src',),
     'exclude_url_prefixes': (),
 }
+
+DIRECTIVES = set(POLICY)
+PSEUDO_DIRECTIVES = {d for d in DIRECTIVES if '_' in d}
diff --git a/csp/conf/deprecation.py b/csp/conf/deprecation.py
index 921503e..2e9d539 100644
--- a/csp/conf/deprecation.py
+++ b/csp/conf/deprecation.py
@@ -3,11 +3,7 @@
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 
-from . import (
-    setting_to_directive,
-    directive_to_setting,
-    DIRECTIVES,
-)
+from . import defaults
 
 
 BLOCK_ALL_MIXED_CONTENT_DEPRECATION_WARNING = (
@@ -21,8 +17,26 @@
 )
 
 
+def setting_to_directive(setting, value, prefix='CSP_'):
+    setting = setting[len(prefix):].lower()
+    if setting not in defaults.PSEUDO_DIRECTIVES:
+        setting = setting.replace('_', '-')
+    assert setting in defaults.DIRECTIVES
+    if isinstance(value, str):
+        value = [value]
+    return setting, value
+
+
+def directive_to_setting(directive, prefix='CSP_'):
+    setting = '{}{}'.format(
+        prefix,
+        directive.replace('-', '_').upper()
+    )
+    return setting
+
+
 _LEGACY_SETTINGS = {
-    directive_to_setting(directive) for directive in DIRECTIVES
+    directive_to_setting(directive) for directive in defaults.DIRECTIVES
 }