Major Land Resource Areas (MLRAs) are designed to support the development and coordination of soil and water conservation programs by the NRCS, with the primary document describing MLRA being Agricultural Handbook #296 (1965, 1978, 1981, and 2006). While the most recent edition of the handbook was released in 2006, many of the geographic boundaries consistently mimic historic map products of generalized regional and national soil-survey maps (some dating back to the 1930s). Furthermore, the underlying concepts and technologies used to build MLRA geography predate adoption of present-day ecological approaches to resource management and conservation. Thus a need has arisen to better develop and define the concepts allowing for “unique and defensible” MLRA geography against neighboring MLRAs. For example, an MLRA must be confined within a physiographic province, contain unique ecological sites/soil map units from its adjoining resource areas, and should incorporate advances in soil climate modeling and data-driven digital soil mapping techniques into MLRA concepts. In preparation for revising the Agricultural Handbook #296, the National Ecological Site Team at the Jornada Experimental Range has underway the compiling of an extensive geographic database of land use, elevation, topography, climate, water resources, potential natural vegetation, and soils. Our approach to developing data-driven MLRA is to use modern geospatial techniques in order to develop a more robust approach to resource area concepts. Our presentation will present the historical development of MLRA concepts and provide recommendations for a national framework in which to create more uniform standards and definitions of MLRA relevant to present day resource and conservation needs.