It is a must to see Millmount Tower and museum. Also Laurences Gate, Magdelene Tower, Old Abbey. These are all within walking distance of each other.
Drogheda is a very old town it has lots of history. St peters church, west st., is another must. It contains a shrine to St. Oliver who was martyered.
Have a visit to the Millmount Tower on the south side of the River Boyne.
The English King, Henry II fortified Millmount. The fort served as a key feature in the defences of Drogheda over the centuries. It was here that many of the defending garrison, including the governor, were slaughtered by Oliver Cromwell's invading army. The Martello tower was built by the British army in 18th-century as part of the nationwide defences against Napoleon.