The closest is Château de Lunéville, 25 km south-east of the city centre; the most famous is Château du Haut-Koenigsbourg — #228 of 8,133 worldwide — 99 km south-east. The oldest dated site in the circle is Château de Pierre-Percée, founded 1100.
The 100 km circle reaches into 3 countries — France (41), Luxembourg (8), Germany (1).