The United States and China were the two most productive countries in global groundwater pollution remediation research, having accumulated substantial findings and practical experience through sustained funding and long-term scientific investment. However, a comprehensive comparative analysis of their research landscapes remained lacking. This study employed bibliometric methods to systematically examine multiple dimensions of groundwater remediation research in both countries over the period 2016–2025, including publication output, journal distribution, core scholars, leading institutions, and funding structures. It visualized research themes and hotspots in both countries through visualization techniques and statistical analysis. The results revealed that both nations ranked as the top two contributors globally in total publication volume during this period, with the U.S. maintaining a higher citation impact per paper. In China, the top 10 universities and research institutes accounted for approximately half of the national output, focusing on remediation materials and microscopic mechanisms under a centralized funding regime dominated by national-level foundations. Conversely, the U.S. fostered a collaborative research ecosystem integrating federal agencies, national laboratories, and universities, characterized by a focus on emerging contaminants and radioactive contaminant remediation, supported by autonomous funding from multiple federal departments. Furthermore, this study examined the heterogeneity in groundwater contamination profiles and regulatory demands between the two nations, alongside differences in funding models, and discussed implications for future development strategies, while acknowledging the inherent limitations of the bibliometric approach. This work provided valuable insights for researchers and policymakers to identify research landscape and optimize strategic layouts in groundwater pollution remediation.