Keila Church is the biggest medieval country church in Harju county, which was obviously established shortly after the North Estonia was occupied by Danes. In 1280 a spacious square chapel was established at "Keila hill", where today there is the chancel of the church. Fragments of the paintings at the chancel walls date possibly from this period already. The main body of the church remained unbuilt at the beginning and was obviously established at the first half of the 14th century. As the influence of the Dominican order, the main body of the church was simple unvaulted box-like building.
The church was expanded in the 15th century. First the massive west-tower was built. Three-sided ending was added to the chancel, it was re-vaulted and altar table of stone was made. In 1480 southern portal was established. In 1489 the church was vaulted and it became two-aisled, which is rather seldom in Estonian churches. The church of Keila was destroyed at the Livonian War in 1558 and the interior was stolen. It was restored in 1596.
There are several chapels in the graveyard, which have been built after 1772 due it was no longer allowed to bury inside churches.
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.