The US Long-term Ecological Research program was started in 1980 to provide ecologists sites at which to address questions that require long periods to resolve. Place-based, hypothesis-driven research that is long-term remains a hallmark of the LTER program today and the foundation of its contributions to earth stewardship. The two overarching research goals of LTER are a) to achieve a mechanistic understanding of ecological responses to past and present environmental change at multiple spatial and temporal scales; and b) to use this understanding to predict ecological, evolutionary, and/or social responses to future environmental change; to inform societal strategies to adapt to and mitigate environmental change; and to conserve, restore, and design ecosystems to improve environmental and human wellbeing. At 26 LTER sites ecologists conduct synthetic and cross-site research that builds upon site-based data, experiments, and models across diverse regions. More and more, LTER research is directed towards network-wide questions at regional to continental scales. Here we will highlight the unique and emerging contributions of long-term ecological research to ecological science, to science education, and to society; synthesize major work, innovative thinking, new approaches, and emerging directions; identify directions for LTER growth in the integration of national observatories and major ecological programs; and underscore the special importance of eco-informatics to long-term research – critical for science and education. Of particular note is the recent emergence of socio-ecological research within the Network, a development that provides a new paradigm for understanding linkages between social and ecological systems. Earth stewardship depends on this understanding – without it, the development of workable policy solutions to some of the most recalcitrant environmental problems of today, ranging from water resource depletion to climate change vulnerability, will remain difficult to design and even more difficult to achieve. New frameworks and long-term research are needed to help us understand how humans perceive the critical services provided by ecosystems, how these perceptions change behavior and institutions, and how behavioral and institutional change in turn feeds back to affect ecosystem structure and function and thereby the ability of ecosystems to deliver future services. In this symposium speakers will use results from 30 years of LTER to illustrate how long-term research can uniquely contribute to the understanding needed to preserve and enhance Earth’s life support systems, and to describe ways in which this legacy can be leveraged to contribute to the ecological theory necessary to address emerging environmental challenges.