diff --git a/system/HTTP/SiteURI.php b/system/HTTP/SiteURI.php
new file mode 100644
index 000000000000..bf3e06903188
--- /dev/null
+++ b/system/HTTP/SiteURI.php
@@ -0,0 +1,312 @@
+<?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 BadMethodCallException;
+use CodeIgniter\HTTP\Exceptions\HTTPException;
+use Config\App;
+
+/**
+ * URI for the application site
+ */
+class SiteURI extends URI
+{
+    /**
+     * The baseURL.
+     */
+    private string $baseURL;
+
+    /**
+     * The Index File.
+     */
+    private string $indexPage;
+
+    /**
+     * List of URI segments in baseURL and indexPage.
+     *
+     * If the URI is "http://localhost:8888/ci431/public/index.php/test?a=b",
+     * and the baseUR is "http://localhost:8888/ci431/public/", then:
+     *   $baseSegments = [
+     *       0 => 'ci431',
+     *       1 => 'public',
+     *       2 => 'index.php',
+     *   ];
+     */
+    private array $baseSegments;
+
+    /**
+     * List of URI segments after indexPage.
+     *
+     * The word "URI Segments" originally means only the URI path part relative
+     * to the baseURL.
+     *
+     * If the URI is "http://localhost:8888/ci431/public/index.php/test?a=b",
+     * and the baseUR is "http://localhost:8888/ci431/public/", then:
+     *   $segments = [
+     *       0 => 'test',
+     *   ];
+     *
+     * @var array
+     *
+     * @deprecated This property will be private.
+     */
+    protected $segments;
+
+    /**
+     * URI path relative to baseURL.
+     *
+     * If the baseURL contains sub folders, this value will be different from
+     * the current URI path.
+     */
+    private string $routePath;
+
+    public function __construct(App $configApp)
+    {
+        // It's possible the user forgot a trailing slash on their
+        // baseURL, so let's help them out.
+        $baseURL = rtrim($configApp->baseURL, '/ ') . '/';
+
+        $this->baseURL   = $baseURL;
+        $this->indexPage = $configApp->indexPage;
+
+        $this->setBaseSeegments();
+
+        // Check for an index page
+        $indexPage = '';
+        if ($configApp->indexPage !== '') {
+            $indexPage = $configApp->indexPage . '/';
+        }
+
+        $tempUri = $this->baseURL . $indexPage;
+        $uri     = new URI($tempUri);
+
+        if ($configApp->forceGlobalSecureRequests) {
+            $uri->setScheme('https');
+        }
+
+        $parts = parse_url((string) $uri);
+        if ($parts === false) {
+            throw HTTPException::forUnableToParseURI($uri);
+        }
+        $this->applyParts($parts);
+
+        $this->setPath('/');
+    }
+
+    /**
+     * Sets baseSegments.
+     */
+    private function setBaseSeegments(): void
+    {
+        $basePath           = (new URI($this->baseURL))->getPath();
+        $this->baseSegments = $this->convertToSegments($basePath);
+
+        if ($this->indexPage) {
+            $this->baseSegments[] = $this->indexPage;
+        }
+    }
+
+    public function setURI(?string $uri = null)
+    {
+        throw new BadMethodCallException('Cannot use this method.');
+    }
+
+    /**
+     * Returns the URI path relative to baseURL.
+     *
+     * @return string The Route path.
+     */
+    public function getRoutePath(): string
+    {
+        return $this->routePath;
+    }
+
+    /**
+     * Returns the URI segments of the path as an array.
+     */
+    public function getSegments(): array
+    {
+        return $this->segments;
+    }
+
+    /**
+     * Returns the value of a specific segment of the URI path relative to baseURL.
+     *
+     * @param int    $number  Segment number
+     * @param string $default Default value
+     *
+     * @return string The value of the segment. If no segment is found,
+     *                throws HTTPException
+     */
+    public function getSegment(int $number, string $default = ''): string
+    {
+        if ($number < 1) {
+            throw HTTPException::forURISegmentOutOfRange($number);
+        }
+
+        if ($number > count($this->segments) && ! $this->silent) {
+            throw HTTPException::forURISegmentOutOfRange($number);
+        }
+
+        // The segment should treat the array as 1-based for the user
+        // but we still have to deal with a zero-based array.
+        $number--;
+
+        return $this->segments[$number] ?? $default;
+    }
+
+    /**
+     * Set the value of a specific segment of the URI path relative to baseURL.
+     * Allows to set only existing segments or add new one.
+     *
+     * @param int    $number The segment number. Starting with 1.
+     * @param string $value  The segment value.
+     *
+     * @return $this
+     */
+    public function setSegment(int $number, $value)
+    {
+        if ($number < 1) {
+            throw HTTPException::forURISegmentOutOfRange($number);
+        }
+
+        if ($number > count($this->segments) + 1) {
+            if ($this->silent) {
+                return $this;
+            }
+
+            throw HTTPException::forURISegmentOutOfRange($number);
+        }
+
+        // The segment should treat the array as 1-based for the user,
+        // but we still have to deal with a zero-based array.
+        $number--;
+
+        $this->segments[$number] = $value;
+
+        $this->refreshPath();
+
+        return $this;
+    }
+
+    /**
+     * Returns the total number of segments.
+     */
+    public function getTotalSegments(): int
+    {
+        return count($this->segments);
+    }
+
+    /**
+     * Formats the URI as a string.
+     */
+    public function __toString(): string
+    {
+        return static::createURIString(
+            $this->getScheme(),
+            $this->getAuthority(),
+            $this->getPath(), // Absolute URIs should use a "/" for an empty path
+            $this->getQuery(),
+            $this->getFragment()
+        );
+    }
+
+    /**
+     * Sets the route path (and segments).
+     *
+     * @return $this
+     */
+    public function setPath(string $path)
+    {
+        $this->routePath = $this->filterPath($path);
+
+        $this->segments = $this->convertToSegments($this->routePath);
+
+        $this->refreshPath();
+
+        return $this;
+    }
+
+    /**
+     * Converts path to segments
+     */
+    private function convertToSegments(string $path): array
+    {
+        $tempPath = trim($path, '/');
+
+        return ($tempPath === '') ? [] : explode('/', $tempPath);
+    }
+
+    /**
+     * Sets the path portion of the URI based on segments.
+     *
+     * @return $this
+     *
+     * @deprecated This method will be private.
+     */
+    public function refreshPath()
+    {
+        $allSegments = array_merge($this->baseSegments, $this->segments);
+        $this->path  = '/' . $this->filterPath(implode('/', $allSegments));
+
+        $this->routePath = $this->filterPath(implode('/', $this->segments));
+
+        if ($this->routePath === '') {
+            $this->routePath = '/';
+
+            if ($this->indexPage !== '') {
+                $this->path .= '/';
+            }
+        }
+
+        return $this;
+    }
+
+    /**
+     * Saves our parts from a parse_url() call.
+     */
+    protected function applyParts(array $parts)
+    {
+        if (! empty($parts['host'])) {
+            $this->host = $parts['host'];
+        }
+        if (! empty($parts['user'])) {
+            $this->user = $parts['user'];
+        }
+        if (isset($parts['path']) && $parts['path'] !== '') {
+            $this->path = $this->filterPath($parts['path']);
+        }
+        if (! empty($parts['query'])) {
+            $this->setQuery($parts['query']);
+        }
+        if (! empty($parts['fragment'])) {
+            $this->fragment = $parts['fragment'];
+        }
+
+        // Scheme
+        if (isset($parts['scheme'])) {
+            $this->setScheme(rtrim($parts['scheme'], ':/'));
+        } else {
+            $this->setScheme('http');
+        }
+
+        // Port
+        if (isset($parts['port']) && $parts['port'] !== null) {
+            // Valid port numbers are enforced by earlier parse_url() or setPort()
+            $this->port = $parts['port'];
+        }
+
+        if (isset($parts['pass'])) {
+            $this->password = $parts['pass'];
+        }
+    }
+}
diff --git a/system/HTTP/URI.php b/system/HTTP/URI.php
index 587e441ffc17..5fb5190184cd 100644
--- a/system/HTTP/URI.php
+++ b/system/HTTP/URI.php
@@ -785,6 +785,8 @@ public function getBaseURL(): string
      * Sets the path portion of the URI based on segments.
      *
      * @return $this
+     *
+     * @deprecated This method will be private.
      */
     public function refreshPath()
     {
diff --git a/tests/system/HTTP/SiteURITest.php b/tests/system/HTTP/SiteURITest.php
new file mode 100644
index 000000000000..3a7c532519f6
--- /dev/null
+++ b/tests/system/HTTP/SiteURITest.php
@@ -0,0 +1,245 @@
+<?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 BadMethodCallException;
+use CodeIgniter\HTTP\Exceptions\HTTPException;
+use CodeIgniter\Test\CIUnitTestCase;
+use Config\App;
+
+/**
+ * @backupGlobals enabled
+ *
+ * @internal
+ *
+ * @group Others
+ */
+final class SiteURITest extends CIUnitTestCase
+{
+    public function testConstructor()
+    {
+        $config = new App();
+
+        $uri = new SiteURI($config);
+
+        $this->assertInstanceOf(SiteURI::class, $uri);
+        $this->assertSame('http://example.com/index.php/', (string) $uri);
+        $this->assertSame('/index.php/', $uri->getPath());
+    }
+
+    public function testConstructorSubfolder()
+    {
+        $config          = new App();
+        $config->baseURL = 'http://example.com/ci4/';
+
+        $uri = new SiteURI($config);
+
+        $this->assertInstanceOf(SiteURI::class, $uri);
+        $this->assertSame('http://example.com/ci4/index.php/', (string) $uri);
+        $this->assertSame('/ci4/index.php/', $uri->getPath());
+    }
+
+    public function testConstructorForceGlobalSecureRequests()
+    {
+        $config                            = new App();
+        $config->forceGlobalSecureRequests = true;
+
+        $uri = new SiteURI($config);
+
+        $this->assertSame('https://example.com/index.php/', (string) $uri);
+    }
+
+    public function testConstructorIndexPageEmpty()
+    {
+        $config            = new App();
+        $config->indexPage = '';
+
+        $uri = new SiteURI($config);
+
+        $this->assertSame('http://example.com/', (string) $uri);
+    }
+
+    public function testSetPath()
+    {
+        $config = new App();
+
+        $uri = new SiteURI($config);
+
+        $uri->setPath('test/method');
+
+        $this->assertSame('http://example.com/index.php/test/method', (string) $uri);
+        $this->assertSame('test/method', $uri->getRoutePath());
+        $this->assertSame('/index.php/test/method', $uri->getPath());
+        $this->assertSame(['test', 'method'], $uri->getSegments());
+        $this->assertSame('test', $uri->getSegment(1));
+        $this->assertSame(2, $uri->getTotalSegments());
+    }
+
+    public function testSetPathSubfolder()
+    {
+        $config          = new App();
+        $config->baseURL = 'http://example.com/ci4/';
+
+        $uri = new SiteURI($config);
+
+        $uri->setPath('test/method');
+
+        $this->assertSame('http://example.com/ci4/index.php/test/method', (string) $uri);
+        $this->assertSame('test/method', $uri->getRoutePath());
+        $this->assertSame('/ci4/index.php/test/method', $uri->getPath());
+        $this->assertSame(['test', 'method'], $uri->getSegments());
+        $this->assertSame('test', $uri->getSegment(1));
+        $this->assertSame(2, $uri->getTotalSegments());
+    }
+
+    public function testSetPathEmpty()
+    {
+        $config = new App();
+
+        $uri = new SiteURI($config);
+
+        $uri->setPath('');
+
+        $this->assertSame('http://example.com/index.php/', (string) $uri);
+        $this->assertSame('/', $uri->getRoutePath());
+        $this->assertSame('/index.php/', $uri->getPath());
+        $this->assertSame([], $uri->getSegments());
+        $this->assertSame(0, $uri->getTotalSegments());
+    }
+
+    public function testSetSegment()
+    {
+        $config = new App();
+
+        $uri = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $uri->setSegment(1, 'one');
+
+        $this->assertSame('http://example.com/index.php/one/method', (string) $uri);
+        $this->assertSame('one/method', $uri->getRoutePath());
+        $this->assertSame('/index.php/one/method', $uri->getPath());
+        $this->assertSame(['one', 'method'], $uri->getSegments());
+        $this->assertSame('one', $uri->getSegment(1));
+        $this->assertSame(2, $uri->getTotalSegments());
+    }
+
+    public function testSetSegmentOutOfRange()
+    {
+        $this->expectException(HTTPException::class);
+
+        $config = new App();
+        $uri    = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $uri->setSegment(4, 'four');
+    }
+
+    public function testSetSegmentSilentOutOfRange()
+    {
+        $config = new App();
+        $uri    = new SiteURI($config);
+        $uri->setPath('one/method');
+        $uri->setSilent();
+
+        $uri->setSegment(4, 'four');
+        $this->assertSame(['one', 'method'], $uri->getSegments());
+    }
+
+    public function testSetSegmentZero()
+    {
+        $this->expectException(HTTPException::class);
+
+        $config = new App();
+        $uri    = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $uri->setSegment(0, 'four');
+    }
+
+    public function testSetSegmentSubfolder()
+    {
+        $config          = new App();
+        $config->baseURL = 'http://example.com/ci4/';
+
+        $uri = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $uri->setSegment(1, 'one');
+
+        $this->assertSame('http://example.com/ci4/index.php/one/method', (string) $uri);
+        $this->assertSame('one/method', $uri->getRoutePath());
+        $this->assertSame('/ci4/index.php/one/method', $uri->getPath());
+        $this->assertSame(['one', 'method'], $uri->getSegments());
+        $this->assertSame('one', $uri->getSegment(1));
+        $this->assertSame(2, $uri->getTotalSegments());
+    }
+
+    public function testGetRoutePath()
+    {
+        $config = new App();
+        $uri    = new SiteURI($config);
+
+        $this->assertSame('/', $uri->getRoutePath());
+    }
+
+    public function testGetSegments()
+    {
+        $config = new App();
+        $uri    = new SiteURI($config);
+
+        $this->assertSame([], $uri->getSegments());
+    }
+
+    public function testGetSegmentZero()
+    {
+        $this->expectException(HTTPException::class);
+
+        $config = new App();
+        $uri    = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $uri->getSegment(0);
+    }
+
+    public function testGetSegmentOutOfRange()
+    {
+        $this->expectException(HTTPException::class);
+
+        $config = new App();
+        $uri    = new SiteURI($config);
+        $uri->setPath('test/method');
+
+        $this->assertSame('method', $uri->getSegment(2));
+        $this->assertSame('', $uri->getSegment(3));
+
+        $uri->getSegment(4);
+    }
+
+    public function testGetTotalSegments()
+    {
+        $config = new App();
+        $uri    = new SiteURI($config);
+
+        $this->assertSame(0, $uri->getTotalSegments());
+    }
+
+    public function testSetURI()
+    {
+        $this->expectException(BadMethodCallException::class);
+
+        $config = new App();
+        $uri    = new SiteURI($config);
+
+        $uri->setURI('http://another.site.example.jp/');
+    }
+}