Tooltip over a Polygon in Google Maps

There's actually a neat trick to work around this (strange) limitation in Google Maps. When moving your mouse over a data item, you can just add a tooltip to the map's <div>. It will be added at the location where your mouse pointer currently is - right over the item!

map.data.addListener('mouseover', mouseOverDataItem);
map.data.addListener('mouseout', mouseOutOfDataItem);

...

function mouseOverDataItem(mouseEvent) {
  const titleText = mouseEvent.feature.getProperty('propContainingTooltipText');

  if (titleText) {
    map.getDiv().setAttribute('title', titleText);
  }
}

function mouseOutOfDataItem(mouseEvent) {
  map.getDiv().removeAttribute('title');
}

I think you will have to do it yourself.In a page i have implemented i attached a mouse move event to the page so i can record the mouse position.Then when a polygon mouseover event occurs i display a custom div near the mouse position

Hope it helps