Telegraph Hill is a nature reserve near Lilley in north Hertfordshire.
It is in the Chilterns Area of Outstanding Natural Beauty (AONB).
The site is a mixture of chalk grassland and scrub, with ancient beech trees.
Wild flowers include rock rose, salad burnet and common spotted orchid.
Between 1796 and 1814 it was a telegraph station,[3] one of the links in the chain between Great Yarmouth and London during the Napoleonic Wars.