diff --git a/system/HTTP/IncomingRequest.php b/system/HTTP/IncomingRequest.php
index 008a865bcdcd..caef09335495 100755
--- a/system/HTTP/IncomingRequest.php
+++ b/system/HTTP/IncomingRequest.php
@@ -235,6 +235,8 @@ protected function detectURI(string $protocol, string $baseURL)
     /**
      * Detects the relative path based on
      * the URIProtocol Config setting.
+     *
+     * @deprecated Moved to SiteURIFactory.
      */
     public function detectPath(string $protocol = ''): string
     {
@@ -265,6 +267,8 @@ public function detectPath(string $protocol = ''): string
      * fixing the query string if necessary.
      *
      * @return string The URI it found.
+     *
+     * @deprecated Moved to SiteURIFactory.
      */
     protected function parseRequestURI(): string
     {
@@ -323,6 +327,8 @@ protected function parseRequestURI(): string
      * Parse QUERY_STRING
      *
      * Will parse QUERY_STRING and automatically detect the URI from it.
+     *
+     * @deprecated Moved to SiteURIFactory.
      */
     protected function parseQueryString(): string
     {
@@ -495,6 +501,9 @@ public function setPath(string $path, ?App $config = null)
         return $this;
     }
 
+    /**
+     * @deprecated Moved to SiteURIFactory.
+     */
     private function determineHost(App $config, string $baseURL): string
     {
         $host = parse_url($baseURL, PHP_URL_HOST);
diff --git a/system/HTTP/SiteURIFactory.php b/system/HTTP/SiteURIFactory.php
new file mode 100644
index 000000000000..e96cc2781f85
--- /dev/null
+++ b/system/HTTP/SiteURIFactory.php
@@ -0,0 +1,251 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\HTTP;
+
+use CodeIgniter\HTTP\Exceptions\HTTPException;
+use Config\App;
+
+class SiteURIFactory
+{
+    /**
+     * @var array Superglobal SERVER array
+     */
+    private array $server;
+
+    private App $appConfig;
+
+    /**
+     * @param array $server Superglobal $_SERVER array
+     */
+    public function __construct(array $server, App $appConfig)
+    {
+        $this->server    = $server;
+        $this->appConfig = $appConfig;
+    }
+
+    /**
+     * Create the current URI object from superglobals.
+     *
+     * This method updates superglobal $_SERVER and $_GET.
+     */
+    public function createFromGlobals(): SiteURI
+    {
+        $routePath = $this->detectRoutePath();
+
+        return $this->createURIFromRoutePath($routePath);
+    }
+
+    /**
+     * Create the SiteURI object from URI string.
+     *
+     * @internal Used for testing purposes only.
+     */
+    public function createFromString(string $uri): SiteURI
+    {
+        // Validate URI
+        if (filter_var($uri, FILTER_VALIDATE_URL) === false) {
+            throw HTTPException::forUnableToParseURI($uri);
+        }
+
+        $parts = parse_url($uri);
+
+        if ($parts === false) {
+            throw HTTPException::forUnableToParseURI($uri);
+        }
+
+        $query = $fragment = '';
+        if (isset($parts['query'])) {
+            $query = '?' . $parts['query'];
+        }
+        if (isset($parts['fragment'])) {
+            $fragment = '#' . $parts['fragment'];
+        }
+
+        $relativePath = $parts['path'] . $query . $fragment;
+
+        return new SiteURI($this->appConfig, $relativePath, $parts['host'], $parts['scheme']);
+    }
+
+    /**
+     * Detects the current URI path relative to baseURL based on the URIProtocol
+     * Config setting.
+     *
+     * @param string $protocol URIProtocol
+     *
+     * @return string The route path
+     *
+     * @internal Used for testing purposes only.
+     */
+    public function detectRoutePath(string $protocol = ''): string
+    {
+        if ($protocol === '') {
+            $protocol = $this->appConfig->uriProtocol;
+        }
+
+        switch ($protocol) {
+            case 'REQUEST_URI':
+                $routePath = $this->parseRequestURI();
+                break;
+
+            case 'QUERY_STRING':
+                $routePath = $this->parseQueryString();
+                break;
+
+            case 'PATH_INFO':
+            default:
+                $routePath = $this->server[$protocol] ?? $this->parseRequestURI();
+                break;
+        }
+
+        return ($routePath === '/' || $routePath === '') ? '/' : ltrim($routePath, '/');
+    }
+
+    /**
+     * Will parse the REQUEST_URI and automatically detect the URI from it,
+     * fixing the query string if necessary.
+     *
+     * This method updates superglobal $_SERVER and $_GET.
+     *
+     * @return string The route path (before normalization).
+     */
+    private function parseRequestURI(): string
+    {
+        if (! isset($this->server['REQUEST_URI'], $this->server['SCRIPT_NAME'])) {
+            return '';
+        }
+
+        // parse_url() returns false if no host is present, but the path or query
+        // string contains a colon followed by a number. So we attach a dummy
+        // host since REQUEST_URI does not include the host. This allows us to
+        // parse out the query string and path.
+        $parts = parse_url('http://dummy' . $this->server['REQUEST_URI']);
+        $query = $parts['query'] ?? '';
+        $path  = $parts['path'] ?? '';
+
+        // Strip the SCRIPT_NAME path from the URI
+        if (
+            $path !== '' && isset($this->server['SCRIPT_NAME'][0])
+            && pathinfo($this->server['SCRIPT_NAME'], PATHINFO_EXTENSION) === 'php'
+        ) {
+            // Compare each segment, dropping them until there is no match
+            $segments = $keep = explode('/', $path);
+
+            foreach (explode('/', $this->server['SCRIPT_NAME']) as $i => $segment) {
+                // If these segments are not the same then we're done
+                if (! isset($segments[$i]) || $segment !== $segments[$i]) {
+                    break;
+                }
+
+                array_shift($keep);
+            }
+
+            $path = implode('/', $keep);
+        }
+
+        // This section ensures that even on servers that require the URI to
+        // contain the query string (Nginx) a correct URI is found, and also
+        // fixes the QUERY_STRING Server var and $_GET array.
+        if (trim($path, '/') === '' && strncmp($query, '/', 1) === 0) {
+            $parts    = explode('?', $query, 2);
+            $path     = $parts[0];
+            $newQuery = $query[1] ?? '';
+
+            $this->server['QUERY_STRING'] = $newQuery;
+            $this->updateServer('QUERY_STRING', $newQuery);
+        } else {
+            $this->server['QUERY_STRING'] = $query;
+            $this->updateServer('QUERY_STRING', $query);
+        }
+
+        // Update our global GET for values likely to have been changed
+        parse_str($this->server['QUERY_STRING'], $get);
+        $this->updateGetArray($get);
+
+        return URI::removeDotSegments($path);
+    }
+
+    private function updateServer(string $key, string $value): void
+    {
+        $_SERVER[$key] = $value;
+    }
+
+    private function updateGetArray(array $array): void
+    {
+        $_GET = $array;
+    }
+
+    /**
+     * Will parse QUERY_STRING and automatically detect the URI from it.
+     *
+     * This method updates superglobal $_SERVER and $_GET.
+     *
+     * @return string The route path (before normalization).
+     */
+    private function parseQueryString(): string
+    {
+        $query = $this->server['QUERY_STRING'] ?? @getenv('QUERY_STRING');
+
+        if (trim($query, '/') === '') {
+            return '/';
+        }
+
+        if (strncmp($query, '/', 1) === 0) {
+            $parts    = explode('?', $query, 2);
+            $path     = $parts[0];
+            $newQuery = $parts[1] ?? '';
+
+            $this->server['QUERY_STRING'] = $newQuery;
+            $this->updateServer('QUERY_STRING', $newQuery);
+        } else {
+            $path = $query;
+        }
+
+        // Update our global GET for values likely to have been changed
+        parse_str($this->server['QUERY_STRING'], $get);
+        $this->updateGetArray($get);
+
+        return URI::removeDotSegments($path);
+    }
+
+    /**
+     * Create current URI object.
+     *
+     * @param string $routePath URI path relative to baseURL
+     */
+    private function createURIFromRoutePath(string $routePath): SiteURI
+    {
+        $query = $this->server['QUERY_STRING'] ?? '';
+
+        $relativePath = $query !== '' ? $routePath . '?' . $query : $routePath;
+
+        return new SiteURI($this->appConfig, $relativePath, $this->getHost());
+    }
+
+    /**
+     * @return string|null The current hostname. Returns null if no host header.
+     */
+    private function getHost(): ?string
+    {
+        $host = null;
+
+        $httpHostPort = $this->server['HTTP_HOST'] ?? null;
+        if ($httpHostPort !== null) {
+            [$httpHost] = explode(':', $httpHostPort, 2);
+
+            if (in_array($httpHost, $this->appConfig->allowedHostnames, true)) {
+                $host = $httpHost;
+            }
+        }
+
+        return $host;
+    }
+}
diff --git a/tests/system/HTTP/SiteURIFactoryDetectRoutePathTest.php b/tests/system/HTTP/SiteURIFactoryDetectRoutePathTest.php
new file mode 100644
index 000000000000..3b7715049a5c
--- /dev/null
+++ b/tests/system/HTTP/SiteURIFactoryDetectRoutePathTest.php
@@ -0,0 +1,227 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\HTTP;
+
+use CodeIgniter\Test\CIUnitTestCase;
+use Config\App;
+
+/**
+ * @backupGlobals enabled
+ *
+ * @internal
+ *
+ * @group Others
+ */
+final class SiteURIFactoryDetectRoutePathTest extends CIUnitTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $_GET = $_SERVER = [];
+    }
+
+    private function createSiteURIFactory(array $server, ?App $appConfig = null): SiteURIFactory
+    {
+        $appConfig ??= new App();
+
+        return new SiteURIFactory($server, $appConfig);
+    }
+
+    public function testDefault()
+    {
+        // /index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/index.php/woot';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath());
+    }
+
+    public function testDefaultEmpty()
+    {
+        // /
+        $_SERVER['REQUEST_URI'] = '/';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = '/';
+        $this->assertSame($expected, $factory->detectRoutePath());
+    }
+
+    public function testRequestURI()
+    {
+        // /index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/index.php/woot';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURINested()
+    {
+        // I'm not sure but this is a case of Apache config making such SERVER
+        // values?
+        // The current implementation doesn't use the value of the URI object.
+        // So I removed the code to set URI. Therefore, it's exactly the same as
+        // the method above as a test.
+        // But it may be changed in the future to use the value of the URI object.
+        // So I don't remove this test case.
+
+        // /ci/index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/index.php/woot';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURISubfolder()
+    {
+        // /ci/index.php/popcorn/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/ci/index.php/popcorn/woot';
+        $_SERVER['SCRIPT_NAME'] = '/ci/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'popcorn/woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURINoIndex()
+    {
+        // /sub/example
+        $_SERVER['REQUEST_URI'] = '/sub/example';
+        $_SERVER['SCRIPT_NAME'] = '/sub/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'example';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURINginx()
+    {
+        // /ci/index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/index.php/woot?code=good';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURINginxRedirecting()
+    {
+        // /?/ci/index.php/woot
+        $_SERVER['REQUEST_URI'] = '/?/ci/woot';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'ci/woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testRequestURISuppressed()
+    {
+        // /woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/woot';
+        $_SERVER['SCRIPT_NAME'] = '/';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('REQUEST_URI'));
+    }
+
+    public function testQueryString()
+    {
+        // /index.php?/ci/woot
+        $_SERVER['REQUEST_URI']  = '/index.php?/ci/woot';
+        $_SERVER['QUERY_STRING'] = '/ci/woot';
+        $_SERVER['SCRIPT_NAME']  = '/index.php';
+
+        $_GET['/ci/woot'] = '';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'ci/woot';
+        $this->assertSame($expected, $factory->detectRoutePath('QUERY_STRING'));
+    }
+
+    public function testQueryStringWithQueryString()
+    {
+        // /index.php?/ci/woot?code=good#pos
+        $_SERVER['REQUEST_URI']  = '/index.php?/ci/woot?code=good';
+        $_SERVER['QUERY_STRING'] = '/ci/woot?code=good';
+        $_SERVER['SCRIPT_NAME']  = '/index.php';
+
+        $_GET['/ci/woot?code'] = 'good';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'ci/woot';
+        $this->assertSame($expected, $factory->detectRoutePath('QUERY_STRING'));
+        $this->assertSame('code=good', $_SERVER['QUERY_STRING']);
+        $this->assertSame(['code' => 'good'], $_GET);
+    }
+
+    public function testQueryStringEmpty()
+    {
+        // /index.php?
+        $_SERVER['REQUEST_URI'] = '/index.php?';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = '/';
+        $this->assertSame($expected, $factory->detectRoutePath('QUERY_STRING'));
+    }
+
+    public function testPathInfoUnset()
+    {
+        // /index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI'] = '/index.php/woot';
+        $_SERVER['SCRIPT_NAME'] = '/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('PATH_INFO'));
+    }
+
+    public function testPathInfoSubfolder()
+    {
+        $appConfig          = new App();
+        $appConfig->baseURL = 'http://localhost:8888/ci431/public/';
+
+        // http://localhost:8888/ci431/public/index.php/woot?code=good#pos
+        $_SERVER['PATH_INFO']   = '/woot';
+        $_SERVER['REQUEST_URI'] = '/ci431/public/index.php/woot?code=good';
+        $_SERVER['SCRIPT_NAME'] = '/ci431/public/index.php';
+
+        $factory = $this->createSiteURIFactory($_SERVER, $appConfig);
+
+        $expected = 'woot';
+        $this->assertSame($expected, $factory->detectRoutePath('PATH_INFO'));
+    }
+}
diff --git a/tests/system/HTTP/SiteURIFactoryTest.php b/tests/system/HTTP/SiteURIFactoryTest.php
new file mode 100644
index 000000000000..294ae9e9844b
--- /dev/null
+++ b/tests/system/HTTP/SiteURIFactoryTest.php
@@ -0,0 +1,91 @@
+<?php
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\HTTP;
+
+use CodeIgniter\Test\CIUnitTestCase;
+use Config\App;
+
+/**
+ * @backupGlobals enabled
+ *
+ * @internal
+ *
+ * @group Others
+ */
+final class SiteURIFactoryTest extends CIUnitTestCase
+{
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $_GET = $_SERVER = [];
+    }
+
+    public function testCreateFromGlobals()
+    {
+        // http://localhost:8080/index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI']  = '/index.php/woot?code=good';
+        $_SERVER['SCRIPT_NAME']  = '/index.php';
+        $_SERVER['QUERY_STRING'] = 'code=good';
+        $_SERVER['HTTP_HOST']    = 'localhost:8080';
+        $_SERVER['PATH_INFO']    = '/woot';
+
+        $_GET['code'] = 'good';
+
+        $factory = new SiteURIFactory($_SERVER, new App());
+
+        $uri = $factory->createFromGlobals();
+
+        $this->assertInstanceOf(SiteURI::class, $uri);
+        $this->assertSame('http://localhost:8080/index.php/woot?code=good', (string) $uri);
+        $this->assertSame('/index.php/woot', $uri->getPath());
+        $this->assertSame('woot', $uri->getRoutePath());
+    }
+
+    public function testCreateFromGlobalsAllowedHost()
+    {
+        // http://users.example.jp/index.php/woot?code=good#pos
+        $_SERVER['REQUEST_URI']  = '/index.php/woot?code=good';
+        $_SERVER['SCRIPT_NAME']  = '/index.php';
+        $_SERVER['QUERY_STRING'] = 'code=good';
+        $_SERVER['HTTP_HOST']    = 'users.example.jp';
+        $_SERVER['PATH_INFO']    = '/woot';
+
+        $_GET['code'] = 'good';
+
+        $config                   = new App();
+        $config->baseURL          = 'http://example.jp/';
+        $config->allowedHostnames = ['users.example.jp'];
+
+        $factory = new SiteURIFactory($_SERVER, $config);
+
+        $uri = $factory->createFromGlobals();
+
+        $this->assertInstanceOf(SiteURI::class, $uri);
+        $this->assertSame('http://users.example.jp/index.php/woot?code=good', (string) $uri);
+        $this->assertSame('/index.php/woot', $uri->getPath());
+        $this->assertSame('woot', $uri->getRoutePath());
+    }
+
+    public function testCreateFromString()
+    {
+        $factory = new SiteURIFactory($_SERVER, new App());
+
+        $uriString = 'http://invalid.example.jp/foo/bar?page=3';
+        $uri       = $factory->createFromString($uriString);
+
+        $this->assertInstanceOf(SiteURI::class, $uri);
+        $this->assertSame('http://localhost:8080/index.php/foo/bar?page=3', (string) $uri);
+        $this->assertSame('/index.php/foo/bar', $uri->getPath());
+        $this->assertSame('foo/bar', $uri->getRoutePath());
+    }
+}