Aim: The aim of this study was to evaluate the patient-, stone-, and anatomy-related factors that may influence the impaction status of proximal ureteral stones, with a particular focus on the ureteral wall thickness (UWT) as a radiologic surrogate marker of chronic irritation. Materials and Methods: A total of 115 adult patients who underwent ureteroscopic treatment for impacted proximal ureteral stones between January 2021 and December 2023 were retrospectively analyzed. The demographic data, comorbidities, stone characteristics (volume, location, and HU value), and anatomical parameters (hydronephrosis grade, proximal ureteral diameter, and UWT) were evaluated using non-contrast computed tomography (NCCT). The correlations between the UWT and both patient- and stone-related variables were assessed using linear and logistic regression analyses. Results: The mean patient age was 45.3 ± 13.8 years, with a male-to-female ratio of 2.11. A significant positive correlation was observed between the UWT and hydronephrosis grade (p = 0.002), presence of comorbidities such as hypertension or diabetes mellitus (p = 0.005), and stone volume (p = 0.005). A larger stone diameter and length were also significantly associated with increased UWT (p = 0.014 and p = 0.005, respectively). However, no statistically significant correlation was found between the UWT and stone density (p = 0.614) or the duration of stone presence (p = 0.987). Conclusions: Increased ureteral wall thickness appears to be a strong indicator of stone impaction severity and is positively associated with hydronephrosis, comorbid conditions, and stone size. These findings support the potential clinical utility of UWT in preoperative planning and treatment selection for impacted upper ureteral stones. Further prospective studies are warranted to validate these observations and explore their implications for procedural success and complication risk.