The establishment of the Archives is the culmination of many years of effort on behalf of the community and County Council. The County's formal attempts to establish an archives began in the late 1980s when local citizens first raised concerns about the lack of a facility to preserve and provide access to the Elgin's archival heritage. In December 1987, a group called "Heritage Elgin - St. Thomas" was formed out of a broad array of heritage organizations to lobby for the creation of a county archives. (View contemporary newspaper coverage of their efforts.)

Elgin County Council immediately responded to these concerns and commissioned a feasibility study for such a program. This study, issued in September 1988, outlined the options and potential costs for an archives. In February 1990, County Council commissioned an engineering firm to assess the feasibility of locating an archival facility on the 4th Floor of the County Administration Building. This study determined that the proposed location did not have sufficient floor-loading capacity to support the weight of the records and the required shelving, although a more intensive study in 2006 revealed that artifact and record storage could be accommodated on the fourth floor. With no other suitable spaces available at the time, the matter was deferred until a more suitable location could be obtained.

Unfortunately, fiscal restraints in the early and mid 1990s prohibited County Council from acting on this matter further despite continuing interest in the community. During this period, the County's library system fortunately continued to accumulate archival records from both public and private sources in anticipation of an archives.

Two factors brought the issue of a county archives back to the forefront in 1998. The first of these was a series of municipal amalgamations within the County, reducing the number of local municipalities from sixteen to seven. Many of these had been in existence since the County's inception and had a significant amount of records. County Council recognized the urgent need to develop an archives to preserve and make available these records in order to promote local accountability and preserve the legacy of these communities for future generations.

The other development was the formation of a new group, the Elgin St. Thomas Archives Association, which took a much more focused approach towards developing an archives. This group secured a broad cross-section of membership not only from the local heritage community, but also from local businesses and professional organizations (for instance, the legal community). The group committed themselves to building strategic partnerships and fundraising on behalf of the archives, in essence acting as a "friends" organization for the program. This moral and potential financial support re-affirmed County Council's own view that there was still strong community "buy-in" to establishing an archives and that the time for action had come.

In May of 2000, the County's Manager of Library Services put forward a report to County Council calling once again for the creation of a county archives. This report took a somewhat different approach than previous attempts in that it called for the hiring of a professional archivist first who would then develop the program and give the initiative the expertise it required, rather than focusing on "bricks and mortar" issues right away. After a lengthy review and hiring process, the County's first archivist, Brian Masschaele, began work in May 2001.

The Archivist subsequently developed a mandate for the program, now called the Elgin County Archives, outlining its purview in terms of acquisition, preservation and public access. This was approved by County Council through a by-law in June 2001. Among its more notable provisions, it called for the acquisition of both municipal and private records, a commitment to preservation and a goal to be a highly visible public resource. In essence, the County made a commitment to go beyond its public obligations to preserve and provide access to its own records to make this program into a total community resource.

The next phase in the development of the archives involved facility planning. The Archivist developed a series of functional criteria, outlining needs in terms of climate-controlled storage, public reference space and staff work areas. Approximately 3,000 square feet of space was made available in the lower level of the Elgin County Administration Building to accommodate this facility (space that was not available in 1990). An independent firm with expertise in archival facility planning then assessed costs to renovate this space - once a cloak room in the former Nurses' Residence of the Ontario Psychiatric Hospital - according to archival standards. Total project costs were assessed at $353,000 inclusive of all taxes, plus architectural fees.

With the costs determined, a Request for Proposals document was immediately developed by the Archivist in conjunction with the County Engineer and Building Maintenance Supervisor to develop this facility within the framework of the assessed cost. This document was submitted to three architectural firms, each selected by the Archivist due to their previous experience and knowledge in archival facility design and climate-controlled environments. At its meeting of September 11, 2001, Elgin County Council endorsed the proposal of the Ventin Group Architects of Simcoe, Ontario to design and manage renovations for this facility. Council also committed itself to funding this project out of an Archives Reserve fund, with the remainder to be secured out of additional reserves and/or fundraising over a four year period. The project was to be completed during 2002 as a Sesquicentennial project for the County of Elgin. At this time, the County also received $128,000 from Heritage Canada’s Cultural Spaces Canada Program, which enabled the County to further enhance the facility.

With the tenders secured, construction of the Archives began in January 2002. Norlon Builders of London, Ontario served as general contractor and Hurok Manufacturing, also of London, installed the electronic mobile shelving systems. The Archives was completed in October 2002 and a grand opening ceremony took place on November 8th, 2002. Elgin County Warden John R. Wilson brought greetings from County Council and officially dedicated the facility to the residents of Elgin County. Elgin-Middlesex-London MP the Honourable Gar Knutson brought greetings from the Government of Canada and unveiled a plaque acknowledging the federal government's important financial contribution to this project through the Cultural Spaces Canada Program. Greetings were also brought forward by Elgin-Middlesex-London MPP Steve Peters and Ms. Miriam McTiernan, Archivist of Ontario. This event held deep meaning to a number of people in the community who worked hard to bring this day to fruition.

As Warden Wilson stated, the timing of this event so close to Remembrance Day, and falling during the County's Sesquicentennial Celebration was only appropriate: "The Archives is itself a hall of memory, a place where future generations will be able to gain a deeper appreciation for all those who have made past sacrifices to preserve the quality of life we enjoy today."