This collection chronicles the day-to-day history of the Mariposa Ranch of Coahuila, Mexico which was owned by Australian brothers and managed by several generations of family friends originally from New Zealand.

The collection spans the years 1880-1955 and consists of three basic parts, personal correspondence, business correspondence, and miscellaneous business papers. Included are letters, diaries, minutes, proceedings, printed material, financial documents, legal documents, photographic and audio material, maps, charts, graphs, and lists that chronicle the history of La Hacienda de la Mariposa and document the hard work and political savvy of the McKellars as they tried to balance the economic and business necessities of running a ranch, with the political realities of the Mexican Revolution and land reform.