Women, especially those from racially and ethnically excluded groups, continue to be underrepresented in the earth and environmental sciences. For this reason, there are multiple programs that seek to diversify the STEM community at all levels, including undergraduate education. Many of these programs, however, lack strong assessment and validation of which activities are successful and why. For these reasons we created the Promoting Geoscience Research, Education and Success (PROGRESS) program in 2015 where we develop, experimentally test, iterate, and scale strategies to support undergraduate women across the geosciences. Our initial program served women in 9 institutions in the Colorado-Wyoming Front Range and Carolinas (USA) regions. Since then we have expanded to 12 additional institutions across Atlanta, Georgia; El Paso, Texas; and College Station, Texas. Women in PROGRESS have access to professional development opportunities, on-line and in-person discussions, and mentoring from a step-ahead geoscientist (e.g., graduate student). Students are also introduced to diverse career role models and other undergraduate women through a workshop experience that encourages them to build their networks, connections, and support systems. In this presentation, I will summarize 4 successful themes for supporting undergraduate women that have emerged from PROGRESS: 1) representation and science identity; 2) early engagement and access to resources; 3) the societal relevance of the geosciences; and 4) communities of support. Finally, improving both access to and the quality of mentoring will continue to be key for retaining women in the earth and environmental sciences. We believe that the lessons we have learned from PROGRESS can be applied to other programs and can be used to build and retain diverse communities in the freshwater sciences.