McArthur River flows southeast to Trading Bay on the west coast of Cook Inlet, approximately 65 miles (105 km) southwest of Anchorage and 29 miles (46 km) northwest of Kenai, Alaska. The river originates at the terminus of McArthur Glacier in the Neacola Mountains and flows for about 9 miles (15 km) before joining the outflow from Blockade Glacier in the Chigmit Mountains, and then continues for another 21 miles (34 km) through the Trading Bay State Game Refuge. The river was named in 1910 after the survey ship McArthur by the U.S. Coast and Geodetic Survey. Trading Bay is a shallow bight extending northeast for 25 miles (40 km) from West Foreland in the south to Granite Point in the north. The bay was named in 1786 by Captain Nathaniel Portlock, who anchored there and traded with the Dena’ina Athabascans. The McArthur River Field, also known as the Trading Bay Unit, is the largest oil field and the fourth-largest gas field in Cook Inlet. The Union Oil Company of California discovered the field in late 1965, and three oil platforms began production in 1968. A fourth platform was constructed in 1987 to tap into deeper oil reservoirs.

The McArthur was a survey ship for the U.S. Coast Survey from 1876 to 1878 and for the U.S. Coast and Geodetic Survey from 1878 to 1915. Built by the Mare Island Navy Yard in 1874 at Vallejo, California, she was named after William P. McArthur, an American naval officer and hydrologist who participated in the first surveys of the Pacific Coast of North America. The ship, powered by a steam engine, measured 121.5 feet (37.0 m) in length, with a beam of 20 feet (6.1 m) and a draft of 7 feet (2.1 m). McArthur served almost exclusively in the waters of the Territory of Alaska. On January 16, 1915, she was in Seattle, Washington, when a fire broke out on the docks. The survey ship Explorer, with its steam engines already running, towed the McArthur and the Thomas R. Gedney to safety. However, the McArthur was surplussed later that year. A series of survey vessels have since been named after William McArthur, including the survey ship McArthur, which served the U.S. Coast and Geodetic Survey from 1966 to 1970, and the National Oceanic and Atmospheric Administration (NOAA) from 1970 to 2003. In 2003, the McArthur II was built as an oceanographic research ship for NOAA.

William P. McArthur was born in 1814 in Sainte Genevieve, Missouri. In 1832, he was appointed as a midshipman at the U.S. Naval School in Norfolk, Virginia. In September 1849, Lieutenant Commander McArthur took command of the U.S. survey schooner Ewing to begin surveying the recently acquired California coast and the western United States coast. Upon reaching San Francisco, Ewing and the USS Massachusetts faced challenges due to crew desertions to the California goldfields. This included a mutiny during which crew members, while rowing into the city, threw an officer overboard in an attempt to desert. McArthur and the remaining crew surveyed Mare Island Strait in San Francisco Bay before sailing to Hawaii to recruit additional crew members. They returned to San Francisco in the spring of 1850 to resume the coastal survey of northern California and continued to the mouth of the Columbia River. Later that year, McArthur fell ill with dysentery and died in Panama. His body was returned to Mare Island for burial. Read more here and here. Explore more of McArthur River and Trading Bay here: