Practical approaches are needed to preserve the health, biodiversity, and resilience of marine ecosystems. Identification of Important Ecological Areas (IEAs) provides a systematic way to prioritize spatial conservation, response, and restoration efforts. We present an analytical method for identifying IEAs in Aleutian Islands large marine ecosystem. Once identified, IEAs should be incorporated into management efforts to avoid unnecessary impacts associated with the exploitation of marine resources. We define Important Ecological Areas as geographically delineated areas which by themselves or in a network have distinguishing ecological characteristics, are important for maintaining habitat heterogeneity or the viability of a species, or contribute disproportionately to an ecosystem's health, including its productivity, biodiversity, functioning, structure, or resilience. As an exercise in valuation, determining “relative importance” requires a process for establishing and comparing values of individual or multiple ecological features on a similar scale, which is accomplished using standard deviates. Ecological features used in this case study included primary productivity, relative abundance of groundfish, marine mammals, seabirds, and habitat-forming invertebrates for which datasets were available. Given the escalating stresses placed on marine habitats generally, a compelling case may be made for assigning the priority to preserving the ecological services provided by IEAs.