Visit British Castles with
Click on a letter above to start your tour.

Examine the links, then explore with Google Earth.
Street view can be rewarding and sometimes you will be able
to follow footpaths or find links inside the castle.

For significant castles, Google usually includes a block like ths:

Click the map, then go to Google Earth. If google has no map
look for Wikipedia where you will often find coordinate links like this:

Clicking on the coordinates will take you to GeoHack - a utility
where you will be able to locate - via numerous options -
your castle on maps or aerial photos.