Human communities across the globe are currently facing an epidemic of lake water quality degradation, primarily resulting from resource and land-use decisions that introduce excessive amounts of nutrients into the lake system. In many of these communities, local volunteer groups called lake associations work to protect these cherished lake resources. Lake associations and similar groups commonly respond to issues that are most prevalent in their respective watersheds including, but not limited to, algae blooms, declines in water transparency, and fish kills. Yet, there is little research on the role these groups actively or potentially play in lake governance and management. This study investigates the specific structures and strategies lake associations use to address lake water quality challenges using a comparative case analysis of two organizations: Lake Sunapee Protective Association (LSPA; Sunapee, NH) and Clean Lakes Alliance (CLA; Madison, WI). I performed a content analysis of self-published newsletters, annual reports, and news publications mentioning either lake association, and supplemented this data with semi-structured interviews of key individuals from each organization. I characterized and compared the missions, capacity, and activity of the two case studies by applying a conceptual framework as a lens through which to better understand the function these groups serve in their communities and what makes them effective. I found that, although the two groups structure themselves differently, take on distinct activity pathways, and orient themselves differently with respect to lake conservation, they have both been effective in achieving decision-making or management outcomes. This is a first step in identifying the diversity of ways community-based conservation organizations, such as lake associations, can meaningfully contribute to collaborative environmental governance processes on the local scale. / Master of Science / Around the world, people who live on lakes are dealing with significant declines in lake water quality. These declines have been linked to various land management decisions, which can introduce excess nutrients to the lake system that promote excessive algal or bacterial growth, and to the ways people choose to use the lake resource, which can introduce non-native, or invasive, plant and animal species. In many lake communities, local volunteer groups called lake associations work to protect their local lake resources. Lake associations can respond to the specific problems facing their lake and act to manage the lake resource and the land around it. Yet, there is little research on the role these groups actively or potentially play in lake management and conservation. This study investigates the specific organizational structures and strategies lake associations and similar groups use to address water quality declines in lake communities. I collected historic documentation and completed oral interviews for two case study associations, Lake Sunapee Protective Association (LSPA; Sunapee, NH) and Clean Lakes Alliance (CLA; Madison, WI), to characterize and compare their missions, organizational capacities, and activities. This analysis allows me to better understand what makes these groups effective and the functions they serve in their communities. I found that, although the two groups are structured differently and implement different strategies to achieve outcomes, they both have been effective in achieving lake management and conservation outcomes in line with their respective missions. This is a first step in identifying the diversity of ways community-based conservation organizations, such as lake associations, can meaningfully contribute to local environmental management and conservation.