The Coastal Monastery of St. Sergius (Сергиева Приморская пустынь) is a Russian Orthodox monastery in the coastal settlement of Strelna near St. Petersburg. It used to be one of the richest monasteries of the Russian Empire and formerly contained seven churches as well as many chapels.
The poustinia was founded in 1734 as a branch of the great Trinity Lavra of St. Sergius in the immediate vicinity of the new Russian capital, St. Petersburg. Catherine Ivanovna, Peter the Great's niece, owned a manor on the bank of the Gulf of Finland. After her death Empress Anna presented the land to her confessor Varlaam, who was also in charge of the Trinity Lavra.
The earliest buildings of the monastery, including the pentacupolar cathedral, the outer wall and the towers, were designed by Pietro Antonio Trezzini. They were Baroque in character. It was not until 1764 that Strelna Monastery was designated a separate poustinia. Many monks from Strelna entered the Navy to serve as ship chaplains. Saint Herman of Alaska was one of those monks.
Some of the noblest and richest families of Imperial Russia, including the Galitzines, the Stroganovs and the Yusupovs, patronised the monastery and had their burial vaults on the grounds. The local cemetery is the burial site of a number of Russian nobles, including the Zubov brothers, Prince Alexander Gorchakov, Duke Peter Georgievich of Oldenburg, and court architect Andrei Stackenschneider. The graves of the Dukes of Oldenburg and Leuchtenberg, both closely related to the Russian imperial family, were either lost or desecrated during the Soviet period.