In November 1855, the Oregon Mounted Volunteers constructed a stockade and two blockhouses across the river from this site on the still smoldering site of the Utilla Indian Agency, which had operated from 1851 to 1855. The fort, named Fort Henrietta after Henrietta Haller, wife of a U.S. Army officer stationed at Fort The Dalles, was named in gratitude for her loan of a wagon to poorly supplied militia. Militia documents suggest it measured 100 feet by 100 feet, with round-log blockhouses at opposite corners and a stockade made from nine-foot split cottonwood rails set in a two-foot-deep trench. Archaeological excavations identified the original stockade through outlines of huge burnt logs and ghosts of burnt posts in the trench, and artifacts from the site included a splitting wedge probably used on the cottonwood logs and a hewing hatchet possibly used in constructing the fort. The militia received orders in April 1856 to abandon and destroy the fort, and in May 1856 the commander reported that it had been destroyed, although settlers' accounts and an 1859 survey indicate that a building, possibly a blockhouse, remained standing and served as a meeting place and arsenal.