The naval port moved to Ust-Amur, and in 1867 Russia sold Alaska to the United States, making Petropavlovsk obsolete as a transit point for traders and explorers on their way to the American territories.
Vojna pomorska luka je premještena u Ust-Amur, a Aljaska je 1867. prodana SAD-u, pa je Petropavlovsk prestao biti tranzitna točka za trgovce i istraživače na putu prema američkim teritorijima.