diff --git a/system/Pager/PagerRenderer.php b/system/Pager/PagerRenderer.php
index a532c36d1163..e7ce557f92ec 100644
--- a/system/Pager/PagerRenderer.php
+++ b/system/Pager/PagerRenderer.php
@@ -81,7 +81,7 @@ class PagerRenderer
 		 */
 	protected $pageCount;
 	/**
-	 * URI? unused?
+	 * URI base for pagination links
 	 *
 	 * @var integer
 	 */
diff --git a/tests/system/HTTP/URITest.php b/tests/system/HTTP/URITest.php
index 9c6d497cb875..579a454a5a91 100644
--- a/tests/system/HTTP/URITest.php
+++ b/tests/system/HTTP/URITest.php
@@ -1,6 +1,8 @@
 <?php
 namespace CodeIgniter\HTTP;
 
+use Config\App;
+use CodeIgniter\Config\Services;
 use CodeIgniter\HTTP\Exceptions\HTTPException;
 
 class URITest extends \CIUnitTestCase
@@ -781,4 +783,61 @@ public function testSetBadSegment()
 		$uri->setSegment(6, 'banana');
 	}
 
+	//--------------------------------------------------------------------
+	// Exploratory testing, investigating https://github.com/codeigniter4/CodeIgniter4/issues/2016
+
+	public function testBasedNoIndex()
+	{
+		Services::reset();
+
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/controller/method';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4';
+		$config->indexPage = 'index.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/controller/method');
+
+		Services::injectMock('request', $request);
+
+		// going through request
+		$this->assertEquals('http://example.com/ci/v4/controller/method', (string) $request->uri);
+		$this->assertEquals('/ci/v4/controller/method', $request->uri->getPath());
+
+		// standalone
+		$uri = new URI('http://example.com/ci/v4/controller/method');
+		$this->assertEquals('http://example.com/ci/v4/controller/method', (string) $uri);
+		$this->assertEquals('/ci/v4/controller/method', $uri->getPath());
+
+		$this->assertEquals($uri->getPath(), $request->uri->getPath());
+	}
+
+	public function testBasedWithIndex()
+	{
+		Services::reset();
+
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/index.php/controller/method';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4';
+		$config->indexPage = 'index.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/index.php/controller/method');
+
+		Services::injectMock('request', $request);
+
+		// going through request
+		$this->assertEquals('http://example.com/ci/v4/index.php/controller/method', (string) $request->uri);
+		$this->assertEquals('/ci/v4/index.php/controller/method', $request->uri->getPath());
+
+		// standalone
+		$uri = new URI('http://example.com/ci/v4/index.php/controller/method');
+		$this->assertEquals('http://example.com/ci/v4/index.php/controller/method', (string) $uri);
+		$this->assertEquals('/ci/v4/index.php/controller/method', $uri->getPath());
+
+		$this->assertEquals($uri->getPath(), $request->uri->getPath());
+	}
+
 }
diff --git a/tests/system/Helpers/URLHelperTest.php b/tests/system/Helpers/URLHelperTest.php
index 564ce6d34796..a5cf314fb7da 100644
--- a/tests/system/Helpers/URLHelperTest.php
+++ b/tests/system/Helpers/URLHelperTest.php
@@ -1,5 +1,4 @@
 <?php
-
 namespace CodeIgniter\Helpers;
 
 use Config\App;
@@ -1085,4 +1084,79 @@ public function testUrlTitleExtraDashes()
 		}
 	}
 
+	//--------------------------------------------------------------------
+	// Exploratory testing, investigating https://github.com/codeigniter4/CodeIgniter4/issues/2016
+
+	public function testBasedNoIndex()
+	{
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/x/y';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4/';
+		$config->indexPage = 'index.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/x/y');
+
+		Services::injectMock('request', $request);
+
+		$this->assertEquals('http://example.com/ci/v4/index.php/controller/method', site_url('controller/method', null, $config));
+		$this->assertEquals('http://example.com/ci/v4/controller/method', base_url('controller/method', null, $config));
+		$this->assertEquals(base_url(uri_string()), current_url());
+	}
+
+	public function testBasedWithIndex()
+	{
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/index.php/x/y';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4/';
+		$config->indexPage = 'index.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/index.php/x/y');
+
+		Services::injectMock('request', $request);
+
+		$this->assertEquals('http://example.com/ci/v4/index.php/controller/method', site_url('controller/method', null, $config));
+		$this->assertEquals('http://example.com/ci/v4/controller/method', base_url('controller/method', null, $config));
+		$this->assertEquals(base_url(uri_string()), current_url());
+	}
+
+	public function testBasedWithoutIndex()
+	{
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/x/y';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4/';
+		$config->indexPage = '';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/x/y');
+
+		Services::injectMock('request', $request);
+
+		$this->assertEquals('http://example.com/ci/v4/controller/method', site_url('controller/method', null, $config));
+		$this->assertEquals('http://example.com/ci/v4/controller/method', base_url('controller/method', null, $config));
+		$this->assertEquals(base_url(uri_string()), current_url());
+	}
+
+	public function testBasedWithOtherIndex()
+	{
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/x/y';
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4/';
+		$config->indexPage = 'fc.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/x/y');
+
+		Services::injectMock('request', $request);
+
+		$this->assertEquals('http://example.com/ci/v4/fc.php/controller/method', site_url('controller/method', null, $config));
+		$this->assertEquals('http://example.com/ci/v4/controller/method', base_url('controller/method', null, $config));
+		$this->assertEquals(base_url(uri_string()), current_url());
+	}
+
 }
diff --git a/tests/system/Pager/PagerTest.php b/tests/system/Pager/PagerTest.php
index bb013a72e8ee..366aa456f239 100644
--- a/tests/system/Pager/PagerTest.php
+++ b/tests/system/Pager/PagerTest.php
@@ -1,6 +1,8 @@
 <?php namespace CodeIgniter\Pager;
 
+use CodeIgniter\HTTP\URI;
 use CodeIgniter\Pager\Exceptions\PagerException;
+use Config\App;
 use Config\Pager;
 use Config\Services;
 
@@ -19,13 +21,22 @@ class PagerTest extends \CIUnitTestCase
 	protected function setUp()
 	{
 		parent::setUp();
-
 		helper('url');
 
-		$_SERVER['HTTP_HOST'] = 'example.com';
-		$_GET                 = [];
-		$this->config         = new Pager();
-		$this->pager          = new \CodeIgniter\Pager\Pager($this->config, Services::renderer());
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/';
+		$_GET                   = [];
+
+		$config          = new App();
+		$config->baseURL = 'http://example.com/';
+		$request         = Services::request($config);
+		$request->uri    = new URI('http://example.com');
+
+		Services::injectMock('request', $request);
+
+		$_GET         = [];
+		$this->config = new Pager();
+		$this->pager  = new \CodeIgniter\Pager\Pager($this->config, Services::renderer());
 	}
 
 	public function testSetPathRemembersPath()
@@ -354,4 +365,32 @@ public function testHeadLinks()
 		$this->assertContains('<link rel="canonical"', $last_page);
 		$this->assertNotContains('<link rel="next"', $last_page);
 	}
+
+	public function testBasedURI()
+	{
+		$_SERVER['HTTP_HOST']   = 'example.com';
+		$_SERVER['REQUEST_URI'] = '/ci/v4/x/y';
+		$_GET                   = [];
+
+		$config            = new App();
+		$config->baseURL   = 'http://example.com/ci/v4/';
+		$config->indexPage = 'fc.php';
+		$request           = Services::request($config);
+		$request->uri      = new URI('http://example.com/ci/v4/x/y');
+
+		Services::injectMock('request', $request);
+
+		$this->config = new Pager();
+		$this->pager  = new \CodeIgniter\Pager\Pager($this->config, Services::renderer());
+
+		$_GET['page'] = 2;
+
+		$this->pager->store('foo', 2, 12, 70);
+
+		$expected = current_url(true);
+		$expected = (string)$expected->setQuery('page=1');
+
+		$this->assertEquals((string)$expected, $this->pager->getPreviousPageURI('foo'));
+	}
+
 }
diff --git a/user_guide_src/source/helpers/url_helper.rst b/user_guide_src/source/helpers/url_helper.rst
index 61e7481407d6..fac7b9c9118f 100644
--- a/user_guide_src/source/helpers/url_helper.rst
+++ b/user_guide_src/source/helpers/url_helper.rst
@@ -30,9 +30,9 @@ The following functions are available:
 	:rtype:	string
 
 	Returns your site URL, as specified in your config file. The index.php
-	file (or whatever you have set as your site **index_page** in your config
+	file (or whatever you have set as your site **indexPage** in your config
 	file) will be added to the URL, as will any URI segments you pass to the
-	function, plus the **url_suffix** as set in your config file.
+	function.
 
 	You are encouraged to use this function any time you need to generate a
 	local URL so that your pages become more portable in the event your URL
@@ -67,7 +67,7 @@ The following functions are available:
 		echo base_url();
 
 	This function returns the same thing as :php:func:`site_url()`, without
-	the *index_page* or *url_suffix* being appended.
+	the *indexPage* being appended.
 
 	Also like :php:func:`site_url()`, you can supply segments as a string or
 	an array. Here is a string example::
@@ -130,7 +130,7 @@ The following functions are available:
 	:returns:	'index_page' value
 	:rtype:	mixed
 
-	Returns your site **index_page**, as specified in your config file.
+	Returns your site **indexPage**, as specified in your config file.
 	Example::
 
 		echo index_page();