The hill of Allen is situated four miles to the north-west of Newbridge, Co. Kildare. Also known as the hill of Almhuin "the Great Neck", it rises 676ft in height and is surrounded by the Bog of Allen.
The Hill of Allen has had many associations with the legendary Fionn MacCumhaill and the Fianna. It is supposed to have been the site of their camp, and the surrounding area was their training ground.
In 1859 Sir Gerald Aylmer of Donadea Castle, began building a tower on the summit of the hill. The tower was circular and had an internal staircase which lead to a glass-domed platform at the top. There were Latin inscriptions in the tower and the names of those who helped construct the tower were engraved on the steps of the staircase. While the tower was being built, giant human bones were discovered, and were said to be those of Fionn MacCumhaill. Sir Gerald ordered that they be re-interred in a hollow space under a rock.
The tower of Allen was completed in 1863. Since then much of the westside of the hill of Allen has being removed by quarrying. However, the intention of Messrs. Roadstone was to leave the hill intact. They also made provisions for restoration work to carried out on the Tower.