diff -rup gmap/gmap_settings_ui.inc gmap-new/gmap_settings_ui.inc
--- gmap/gmap_settings_ui.inc	2010-06-08 20:49:13.000000000 +0000
+++ gmap-new/gmap_settings_ui.inc	2012-06-05 20:42:11.000000000 +0000
@@ -327,6 +327,7 @@ function gmap_admin_settings(&$form_stat
     'marker' => 'cluster',
     'max_nocluster' => 150,
     'cluster_min' => 5,
+    'grid_size' => 5,
     'max_lines' => 10,
     'popup_mode' => 'orig',
   ), $opts['clusterer']);
@@ -548,6 +549,15 @@ function gmap_admin_settings(&$form_stat
     '#maxlength' => 3,
     '#default_value' => $opts['clusterer']['cluster_min'],
   );
+  $form['gmap_markermanager']['clusterer']['grid_size'] = array(
+    '#type' => 'textfield',
+    '#title' => t('Grid size'),
+    '#field_suffix' => t('markers acrross map width'),
+    '#description' => t("The size of the grid used for placing the clusters. The default value of 5 indicates that there can be 5 clusters from east to west across the map."),
+    '#size' => 3,
+    '#maxlength' => 3,
+    '#default_value' => $opts['clusterer']['grid_size'],
+  );
   $form['gmap_markermanager']['clusterer']['max_lines'] = array(
     '#type' => 'textfield',
     '#title' => t('Lines per box'),
diff -rup gmap/js/clusterer_marker.js gmap-new/js/clusterer_marker.js
--- gmap/js/clusterer_marker.js	2009-02-12 23:45:23.000000000 +0000
+++ gmap-new/js/clusterer_marker.js	2012-06-05 20:35:54.000000000 +0000
@@ -23,6 +23,7 @@ Drupal.gmap.addHandler('gmap', function 
       obj.clusterer.SetMaxVisibleMarkers(+s.max_nocluster);
       obj.clusterer.SetMinMarkersPerCluster(+s.cluster_min);
       obj.clusterer.SetMaxLinesPerInfoBox(+s.max_lines);
+      obj.clusterer.gridSize = s.grid_size;
     }
   });