diff -u b/modules/redirect_404/config/install/redirect_404.settings.yml b/modules/redirect_404/config/install/redirect_404.settings.yml
--- b/modules/redirect_404/config/install/redirect_404.settings.yml
+++ b/modules/redirect_404/config/install/redirect_404.settings.yml
@@ -1 +1 @@
-row_limit: 100
+row_limit: 3
diff -u b/modules/redirect_404/redirect_404.module b/modules/redirect_404/redirect_404.module
--- b/modules/redirect_404/redirect_404.module
+++ b/modules/redirect_404/redirect_404.module
@@ -4,7 +4,9 @@
  * @file
  * Cleanup 404 errors dblog for path that has already a redirect assigned.
  */
+
 use Drupal\language\Entity\ConfigurableLanguage;
+use Drupal\Core\Form\FormStateInterface;
 
 /**
  * @defgroup redirect_api Redirection API
@@ -32,0 +35,56 @@
+
+/**
+ * Implements hook_cron().
+ *
+ * Controls the size of the log table, paring it to 'dblog_row_limit' messages.
+ */
+function redirect_404_cron() {
+  // Cleanup the watchdog table.
+  $row_limit = \Drupal::config('redirect_404.settings')->get('row_limit');
+
+  // For row limit n, get the wid of the nth row in descending wid order.
+  // Counting the most recent n rows avoids issues with wid number sequences,
+  // e.g. auto_increment value > 1 or rows deleted directly from the table.
+  if ($row_limit > 0) {
+    $query = \Drupal::database()->select('redirect_404', 'r404')
+      ->extend('Drupal\Core\Database\Query\TableSortExtender')
+      ->orderBy('count', 'DESC')
+      ->orderBy('timestamp', 'DESC')
+      ->extend('Drupal\Core\Database\Query\PagerSelectExtender')
+      ->limit($row_limit - 1)
+      ->fields('r404', ['timestamp'])
+      ->execute()->fetchField();
+
+    // Delete all table entries older than the nth row, if nth row was found.
+    if ($query) {
+      \Drupal::database()->delete('redirect_404')
+        ->condition('timestamp', $query, '<')
+        ->execute();
+    }
+  }
+}
+
+/**
+ * Implements hook_form_FORM_ID_alter() for system_logging_settings().
+ */
+function redirect_404_form_system_logging_settings_alter(&$form, FormStateInterface $form_state) {
+  $row_limits = [100, 1000, 10000, 100000, 1000000];
+  $form['dblog_row_limit'] = [
+    '#type' => 'select',
+    '#title' => t('404 error database logs to keep'),
+    '#default_value' => \Drupal::configFactory()->getEditable('redirect_404.settings')->get('row_limit'),
+    '#options' => [0 => t('All')] + array_combine($row_limits, $row_limits),
+    '#description' => t('The maximum number of 404 error logs to keep in the database log. Requires a <a href=":cron">cron maintenance task</a>.', [':cron' => \Drupal::url('system.status')])
+  ];
+
+  $form['#submit'][] = 'redirect_404_logging_settings_submit';
+}
+
+/**
+ * Form submission handler for system_logging_settings().
+ *
+ * @see redirect_404_form_system_logging_settings_alter()
+ */
+function redirect_404_logging_settings_submit($form, FormStateInterface $form_state) {
+  \Drupal::configFactory()->getEditable('redirect_404.settings')->set('row_limit', $form_state->getValue('dblog_row_limit'))->save();
+}