Background and Purpose: The objective of this research is to analyze and investigate the foundations of spatial segregation in the city of Borujerd. Most domestic studies on segregation have primarily focused on socio-cultural foundations, relying on data from the Statistical Center of Iran and questionnaire surveys.  Most of these studies have been conducted in metropolitan areas, with limited research addressing small and medium-sized cities. In all these studies, the dual spatial structure of cities—namely, the division between northern and southern areas—is evident. However, recent research has begun to emphasize the role of emerging factors such as the COVID-19 pandemic, climate change, and virtual social networks.
Methodology: This research is fundamental-applied in terms of objective and follows an descriptive-analytical method based on direct observations and questionnaire distribution. The primary spatial units of analysis are the urban neighborhoods of Borujerd, which are classified into five distinct clusters: marginalized neighborhoods, annexed villages, privileged neighborhoods, pre-planned residential complexes, and the city's historical core neighborhoods. Data collection was conducted through both documentary and field research methods. To identify the influential factors in socio-economic segregation among different areas of Borujerd, questionnaires were distributed using simple random sampling, with the number of questionnaires allocated proportionally to each cluster's population. The study population comprises all residents of Borujerd, which had a total population of 249,337 according to the 2016 national census. The sample size was determined using Cochran's formula, resulting in 384 completed questionnaires.
Findings and Discussion: In marginalized neighborhoods, the presence of extended family and tribal affiliations emerges as the most significant factor in residential choice. For annexed villages, respondents identified two primary determinants: the absence of overcrowding and the presence of kinship networks. Residents of privileged neighborhoods prioritize different criteria, with two factors being particularly influential: the lack of population density and cultural homogeneity, particularly in terms of educational attainment levels among neighbors. Pre-planned residential complexes demonstrate a more complex set of considerations, where three factors play crucial roles: low population density, cultural similarity in educational backgrounds, and the perceived absence of criminal activity. The historical core neighborhoods of the city show similar patterns to the planned complexes, with residents valuing the same three factors: minimal crowding, cultural/educational homogeneity, and low crime rates.
Conclusion: Spatial segregation is not merely a physical or economic phenomenon but is significantly influenced by social, cultural, and security factors. The findings reveal that individuals  prefer living in neighborhoods with socio-cultural homogeneity, where conditions such as high security, similar educational levels, low population density, and the presence of relatives or close kin are maintained. These preferences lead to the formation of class-homogeneous or ethnically homogeneous neighborhoods, which in turn intensify spatial segregation. The spatial distribution of low, middle, and high socio-economic groups in Borujerd is distinctly clustered, a pattern shaped by the metrics used to construct the city's different socio-economic strata. This clustering pattern results from urban planning systems that have focused on developing pre-planned residential complexes and expanding facilities and services in privileged neighborhoods and the city's historical core, while neglecting the expansion of marginalized neighborhoods and annexed villages. The study demonstrates that spatial segregation in Borujerd manifests through clear divisions between northern and south areas, with the southern part of the city accommodating lower socio-economic groups and the north part housing middle- upper class residents.