Objective: This study utilized the evidence-gap map method and critically examined the scope, methodologies, and focus of the studies that investigated the influence of the built environment on inpatient healthcare settings over a decade (2010–2021). Methods: We conducted a systematic review per the preferred reporting items for systematic reviews and meta-analyses guidelines and surveyed 406 articles, primarily from North America and Europe. Results: Our findings revealed a dominant focus on architectural features (73%), such as room design and ward layout. Comparatively, there was less emphasis on interior-, ambient-, social-, and nature-related features. Most previous studies explored multiple environmental features, which indicated the intricacy of this field. Research outcomes were diverse, with person-centered care (PCC) being the most frequently investigated, followed by safe care, emotional well-being, activity, and behavior. Furthermore, research methods varied considerably based on the study’s outcomes and features. Clinical outcomes and safe care favored quantitative methods, activity and behavior favored mixed methods, and PCC favored qualitative research. Conclusion: This review provides an in-depth overview of the existing studies on healthcare design research and sheds light on the current trends and methodological choices. The insights garnered can guide future research, policy-making, and the development of healthcare facilities.