In 1871, U.S. officials sought to open up what was then Corea (now Korea) to trade and secure a commerce agreement through peaceful negotiations. In May 1871, a Naval squadron, including U.S.S. Monocacy, Palos, Alaska, and Colorado, under RADM John Rodgers anchored in the Salee River near Inchon and talks between the two nations commenced. All seemed to be going well and RADM Rodgers secured permission to send a surveying party up the river past the five forts that lined the banks to map the area for the safety of future commerce and navigation. However, as the surveyors carried out their mission above the forts, the party was fired upon from both the forts and the shore. The landing party was quickly rescued but the diplomatic damage was done.
The U.S. demanded an apology but none was given. On 10 June, a force of bluejackets and Marines were sent ashore with orders to take the five forts which guarded the river. The four steam-launches carrying a battalion of Marines, a brigade of seamen infantry, and seven field pieces, soon came under fire from the forts. U.S.S. Monocacy and Palos quickly returned fire, allowing the first wave of the landing party, the Marines, to reach the shore safely. The Marines quickly overtook the first fort and began dismantling it. The following morning, the Marines once again led the charge against Corea’s second line of fortification, but the advance was unopposed, allowing attention to be turned to citadel.
The citadel, the chief offender of the attack on the surveyors, sat high upon a steep hill with high walls that would have been impossible to scale if not for the guns of U.S.S. Monocacy and the few artillery pieces that had been brought to shore. Once the walls were down, Marines and sailors swarmed over the parapet and engaged the Corean forces. The fort’s defenders fought to the last man but eventually fell to the American forces. The two remaining forts made no resistance. The landing party returned to the ships on the morning of 12 June having suffered only two casualties, one Marine killed and one Marine wounded. Six Marines and nine sailors were awarded the Medal of Honor for their participation in the capture of the Corean forts.
In October 2007, the U.S. Naval Academy agreed to temporarily loan to the Republic of South Korea the large flag the Marines had captured during the brief 1871 battle. The giant banner had been displayed in the Naval Academy museum since undergoing preservation treatments in 1913.