Allegheny County formed the first LAAOH (Ladies Auxiliary of the Ancient Order of Hibernians), the forerunner of the LAOH, in 1897. Division 1 was located in the East area of the city, and came about through the efforts of Eliza Abbott, Margaret McNamara and Past AOH County President John J. Reilly. On August 16, 1898, Allegheny County was formed with Elza as President, though the National records of 1902 record Margaret J. Melia as President.

The LAAOH was favorably received because the great number of young Irish immigrant girls welcomed the opportunity for fellowship and support. Margaret J. Melia was the catalyst in organizing divisions until her early death in 1914 at the age of 39. Through her leadership an interest was developed in assisting not only the young immigrants but also the orphans. Her accomplishments were so great that a monument was placed on her grave as a joint contribution of both the AOH and LAAOH. In 1986, the Allegheny County women had the monument restored.

Allegheny County has had many members on the National Board in many official positions including three presidents - Mary Timon Horan (1924 – 1928), Lenora Shea (1948 – 1952), and Margaret Cooney (1998 – 2000). The County has also had a number of officers on the State Board. Since 1960, Presidents have included Anne Gibbons, Catherine Dougherty, Alice Murray, Mae O'Grady, Sara Madigan, Margaret Cooney, Sarah Mains, and Judi Coyne. Many other State Board members have served from Allegheny County .

From 1945 – 1974 the County had a Degree Team, and in 1985 the Team was reactivated as the Claddagh Degree Team of Allegheny County. Both teams exemplified the major Degrees on the County, State, and National level.

The County supports all State and National projects and events including the Irish History contest and joins with the AOH in various events such as the Annual St. Patrick's Day Communion Breakfast and the St. Patrick's Day Parade. The County instituted the St. Brigid Mass during which the formal installation ceremony for all the Division Officers is held.

In 1985, the County hosted the joint AOH and LAAOH National Board meeting and completed the work begun at the 1982 National Convention in San Antonio , TX . The new Constitution was completed and signed by the A.O.H. National President, Joseph A. Roche in October 1985 at the Joint National Board meeting . By the signing of the Constitution, the word "Auxiliary" was deleted and the organization assumed its new name, Ladies Ancient Order of Hibernians, and jurisdiction over its own affairs. In 2004, the LAOH became incorporated, becoming known as the Ladies Ancient Order of Hibernians, Inc.

Allegheny County is proud of the fact that the Board has had a continuous history since 1898, as have 2 Divisions – Division 11 since 1906 and Division 21 since 1908.