Llanallgo (Welsh: [ɬanˈaɬɡɔ]) is a small village a mile from the coast of the island of Anglesey.

[1] St Gallgo's Church, contains a memorial to hundreds lost when the Royal Charter bound from Australia to Liverpool hit the nearby Moelfre rocks.

The monument is said to be of marble cut from near where the ship was lost on 26 October 1859.

[2] Nearby is Ffynnon Allgo, a medieval well which is a scheduled monument.

The nearest larger village is Marian-glas, about 1 km to the south.