O’Brien Post 177 received its Charter on October 27th, 1919. It is one of the oldest organizations in the community and in the American Legion. The American Legion was formed in July, 1919.

The Charter Members of the Post were Harold M. Clark, Sanford E. Rock, John Grotha, Orris J. Wright, Clarence P. Chartrand, Walter Wehrle, Guy E. Johnson, Orbit S. Peppers, Gerald L. Brundage, I. Delmain, George Payne, Zona V. Boland, Arley E. Brundage, Elbert Delmain, Clarence Wehrle, and Victor E. Mottert.

The name of the Post was selected to honor the memory of the late Marine Corporal Leo P. O’Brien, son of Mr. and Mrs. Patrick O’Brien. Corporal O’Brien was born February 28, 1893 at Burnsville, Missouri. He enlisted in the Marine Corps on August 1, 1917 in St. Louis and received his recruit training at the Marine Base, Parris Island, SC. He sailed for France with the Third Replacement Battalion aboard the USS Von Stuben on February 5, 1918, and was promoted to the rank of Corporal two days later.

Corporal O’Brien participated in action against the enemy in June, 1918, in the Chateau Thierry Sector. He was killed in action by gas on July 31, 1918, while fighting in the Soissons Sector with Company F, 5th Marine Regiment. His medals and decorations include: Victory medal with Aisme-Marne Battle Clasp, Defensive Sector Clasp with two Bronze Stars, and the French Fourragere. He was buried in the American Cemetery at Ploisy, France, disinterred in May, 1921, and is now buried in the National Cemetery at Jefferson Barracks, St. Louis County, Missouri.

In the early stages of the organization, meetings were held in a variety of locations; in homes, Justice of the Peace Court, Town Pool Hall, Eureka High School, Times Beach Community House, Post Home on Old Highway 66, and the old Powder Magazine in a field west of Eureka. In March 1955, 11.47 acres was purchased from Ed Sutter located on Bald Hill Road where construction of a new Post Home was begun on October 22, 1956. Completion and dedication was in April, 1957. Members put in long hours finishing the building, installing a flag pole, and building the parking lot. Due to their inability to maintain the property, this building and property was sold to the City of Eureka on June 12, 1984, which now serves the community as the Eureka Community Center.

In 1948, the Post started an annual carnival to raise funds for community activities. Today this activity is known as Eureka Days and has come to be a very popular event annually.

Membership has fluctuated over the years from a high of 216 in 1972 to a low in recent times of 101 in 1988. Today, for the year 2010 our current membership is 128.