The Gansu–Qinghai–Ningxia region is a major area of concentrated Hui settlement in northwestern China, characterized by significant cultural interaction and integration. In response to the limited regional-scale research on how multiple cultural and geographical factors jointly shape settlement spatial forms, this study adopts a cultural integration perspective and develops an analytical framework of “field investigation–settlement morphology–historical tracing–cultural interpretation.” Eleven representative traditional Hui settlements and historical residential areas in Gansu, Qinghai, and Ningxia are selected as case studies. Based on field surveys, spatial mapping, and an examination of local gazetteers and historical documents, the study identifies the spatial characteristics of these settlements and traces their historical and cultural origins. Four major spatial types are identified: settlements organized around mosques, differentiated hierarchical settlements, fortress-based settlements, and settlements shaped by commercial activities. The study argues that the long-term interaction among the distinctive frontier environment, multicultural integration, shared religious beliefs, and transregional trade networks has jointly produced the multilayered spatial patterns of Hui settlements in the region. This research establishes an analytical approach that integrates geographical, religious, commercial, and ethnic-cultural factors, providing a useful reference for the study and conservation of traditional settlements and cultural heritage in the multiethnic regions of northwestern China.