diff --git a/system/core/URI.php b/system/core/URI.php
index 15e6a55..40eaaeb 100644
--- a/system/core/URI.php
+++ b/system/core/URI.php
@@ -433,9 +433,9 @@
 	/**
 	 * Generate a key value pair from the URI string or Re-routed URI string
 	 *
-	 * @param	int	the starting segment number
-	 * @param	array	an array of default values
-	 * @param	string	which array we should use
+	 * @param	int	$n = 3			the starting segment number
+	 * @param	array	$default = array()	an array of default values
+	 * @param	string	$which = 'segment'	which array we should use
 	 * @return	array
 	 */
 	protected function _uri_to_assoc($n = 3, $default = array(), $which = 'segment')
@@ -445,9 +445,11 @@
 			return $default;
 		}
 
-		if (isset($this->keyval[$n]))
+		in_array($which, array('segment', 'rsegment'), TRUE) OR $which = 'segment';
+
+		if (isset($this->keyval[$which], $this->keyval[$which][$n]))
 		{
-			return $this->keyval[$n];
+			return $this->keyval[$which][$n];
 		}
 
 		if ($which === 'segment')
@@ -499,7 +501,7 @@
 		}
 
 		// Cache the array for reuse
-		$this->keyval[$n] = $retval;
+		$this->keyval[$which][$n] = $retval;
 		return $retval;
 	}
 
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 8576dbf..d3cebc7 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -380,6 +380,7 @@
 -  Fixed a bug (#191) - :doc:`Loader Library <libraries/loader>` ignored attempts for (re)loading databases to ``get_instance()->db`` even when the old database connection is dead.
 -  Fixed a bug (#1255) - :doc:`User Agent Library <libraries/user_agent>` method ``is_referral()`` only checked if ``$_SERVER['HTTP_REFERER']`` exists.
 -  Fixed a bug (#1146) - :doc:`Download Helper <helpers/download_helper>` function ``force_download()`` incorrectly sent *Cache-Control* directives *pre-check* and *post-check* to Internet Explorer.
+-  Fixed a bug (#1811) - :doc:`URI Library <libraries/uri>` didn't properly cache segments for ``uri_to_assoc()`` and ``ruri_to_assoc()``.
 
 Version 2.1.3
 =============