This study examined whether headwater streams located within protected areas in Maryland exhibited less impacted ecological conditions compared to adjacent unprotected streams. The study analyzed landscape features, water quality variables, and biological indicators at 148 protected areas and 474 unprotected stream sites across three regions of Maryland. Results showed that protected area streams had significantly less urban and agricultural land use and better habitat quality. While water quality differences were small, protected streams in some regions showed marginally better quality. Landscape factors at broader spatial scales influenced stream conditions more than local factors in protected areas. Therefore, the study found that protected areas can effectively filter water quality impacts from surrounding land uses in some areas of Maryland.