Saltwater intrusion, the landward movement of marine salts, is becoming an increasing problem in coastal areas due to sea level rise, storm surge, drought, and hydrologic modification of freshwaters. Saltwater intrusion has clearly documented impacts on terrestrial ecosystems such as killing coastal trees, changing greenhouse gas emissions from wetlands, and reducing the productivity of farmland. But how this change in salinity affects river environments is less clear. To evaluate the impact of saltwater intrusion on coastal river ecosystems, we assessed changes in river color, an integrative metric of many important ecosystem parameters. We used the Harmonized Landsat-Sentinel and an integrated Landsat dataset to extract river reflectance values from National Hydrography Dataset river reaches wider than 60m in the U.S. southeast. We looked at long-term trends in river color (1985-present) and seasonal patterns along the river environments. In a preliminary analysis of North Carolina rivers, we found most river reaches have darkened (78%) since 1985. We also found a positive correlation between drought and river greenness in 15% of river reaches, most of which occurred near the outlet of the river. Although remote sensing is a powerful tool that allows exploration across large scale, in this case it lacks the ability to identify the mechanisms behind observed changes. We speculate changes in river brightness could either be caused by reductions in suspended sediment or increases in dissolved organic matter, both of which have been observed across many U.S. rivers. The relationship between drought and river greenness we suspect is caused by flocculation of dissolved organic matter by divalent cations in sea salt. This phenomenon is known to occur in organic rich waters and could lead to clearer water, which has higher green reflectance, or could increase light availability and allow growth of algae. In our analysis, we observe widespread changes in southeastern rivers but lack the ability to definitively attribute these changes to any one mechanism. Future work should explore the cause of change in river brightness and the impact of saltwater intrusion on coastal river ecosystems.