The El Toro Reuse Planning Authority (ETRPA) is a joint powers authority commissioned with developing a non-aviation reuse alternative for El Toro Marine Corps Air Station (MCAS/El Toro).

ETRPA is comprised of eleven board members representing the nine South Orange County cities of Dana Point, Irvine, Laguna Beach, Laguna Hills, Laguna Niguel, Laguna Woods, Lake Forest, Mission Viejo, and Ranch Santa Margarita.

The founding of ETRPA dates to March 1994 when Orange County, Lake Forest and Irvine were charged with devising two non-aviation plans and one aviation plan for MCAS/El Toro. ETRPA completed the baseline documentation for closing MCAS/El Toro, including an inventory of existing uses and facilities, and prepared an environmental report.

Orange County voters passed Measure A in November 1994 amending the county's General Plan by designating MCAS/El Toro as an international commercial airport. As a result, Orange County withdrew from participation in ETRPA.

The following year, upon aggressive lobbying of the Department of Defense, Orange County was designated as the Local Redevelopment Authority (LRA) under the Base Realignment and Closure Act. This entitles the Orange County Board of Supervisors final authority over development at El Toro, following its closure in 1999.

ETRPA expanded its membership in 1995 to include the cities of Laguna Hills, Mission Viejo, Laguna Niguel, Dana Point and Laguna Beach.  (Laguna Woods, formerly Liesure World, bcame a member soon after becoming a city in 1999.)  ETRPA also undertook its own analysis of the maximum aviation potential of MCAS/El Toro and, as part of the comments on the Federal Environmental Impact Statement, prepared modifications to the county's preliminary non-aviation plan to increase its economic development potential.

In December 1996, the Orange County Board of Supervisors directed its staff to undertake preparation of an aviation master plan and a "parallel process" non-aviation specific plan. Under public criticism that the county overspent on developing an aviation plan at the expense of a non-aviation plan, the Board of Supervisors commissioned ETRPA in October 1997 to develop the non-aviation plan.

Within six months and after an exhaustive, open planning process that engaged the community though an outreach effort that included input from residents, businesses and civic organizations throughout the county, ERTPA returned with The Millennium Plan. Public input garnered from community meetings and workshops helped shape the plan by ETRPA's technical planning team of urban planners, financial consultants and land use experts.

ETRPA presented The Millennium Plan to the Orange County Board of Supervisors on March 31, 1998, where it now stands as the official non-aviation reuse alternative by which a commercial airport plan will be measured.