Gerasim Grigoryevich Izmaylov (Russian:Герасим Григорьевич Измайлов;circa 1745 –after 1795) was a Russian navigator involved in theRussian colonization of the Americas and in the establishment of the colonies ofRussian America inAlaska. He was responsible for the first detailed maps of theAleutian Islands.
A native ofYakutsk, Izmaylov attended a navigation school inOkhotsk with Dmitry Bocharov, who became his lifelong business companion. In 1771, both were caught up in theBenyovszky mutiny atBolsheretsk onKamchatka. Izmaylov attempted to break away from the mutineers but, after being flogged, was marooned on the isle ofSimushir, one of the uninhabitedKuril Islands. For a year he subsisted on "scallops, grass, and roots" before being rescued byyasak gatherers. He was investigated inIrkutsk on account of his association with Benyovszky, but was eventually cleared of all charges in 1774.
In 1775, Izmaylov assumed command of the boatSt. Paul and set to work mapping the shores of theAleutian Islands. In October 1778, while visitingUnalaska, he made the acquaintance of CaptainJames Cook who presented him with an octant in exchange for a letter of introduction to theKamchatka authorities. Cook also handed over to Izmaylov a recently drawn map of the western coast of North America, which was to be delivered by the Russians to theBritish Admiralty.
In 1783–1785, Izmaylov andGrigory Shelikhov made their historic voyage from Okhotsk toKodiak Island, where they founded the first Russian settlement in America. In 1789, Izmaylov became the first to explore and map theKenai Peninsula. Three years later, he took up employment underAlexander Baranov, helping him withstand a sea attack by theTlingit.
Having wintered in Unalaska, Izmaylov visitedSaint Paul Island, where he discovered the crew of a Russian ship that had been missing since 1791. He brought them back to Okhotsk in June 1794. He is mentioned for the last time in 1795, when he accompanied to Alaska a group of Orthodox missionaries underFather Joasaph.