Lamia preserves a substantial stretch of its ancient defensive walls on the northern and western slopes of the castle hill. Built in the Hellenistic period, when Lamia was an important city of the Aenianes — the indigenous tribe of the Spercheios valley — and later a Macedonian garrison town, the walls are constructed in the careful polygonal masonry characteristic of the period. Some sections stand to nearly their full original height.
The walls are freely accessible and most easily reached by walking up from the town centre toward the castle. They are not well-signed, and finding the best-preserved sections requires a little wandering — which is half the pleasure. The area around the walls has been lightly landscaped as a park, and it makes a quiet alternative to the busier castle precinct. Lamia was the centre of the Lamian War (323–322 BC), in which the Greek city-states attempted to throw off Macedonian rule after the death of Alexander the Great; these walls were likely strengthened in that period.