Records documenting most aspects of the activities of the Muskoka Lakes Association from 1894 to the 1990s, with some gaps in coverage. Materials present include correspondence, committee minutes and annual reports, financial records, legal records, publications, ephemera, audiovisual material, and artifacts.

Accrual consists of material documenting aspects of the administration and activities of the Muskoka Lakes Association and some of its committees, mainly during the period from 1978 to 2003. During this time, the primary political and environmental concerns of the association included land use and resort development, taxation, water quality, and relationships with municipal and provincial governments.

Accrual contains records created and accumulated by chairs of political, environmental, and land use committees and by several presidents, as well as records relating to office administration and other committees and activities of the association.

Includes correspondence and memoranda; reports; presentations; committee minutes and agendas; newspaper clippings; publications; handwritten and typed notes; notices and decisions of provincial judicial boards; official plans, by-laws and other municipal documents; maps and architectural drawings; ephemera; and other material.