Objectives In 2020, firearm injuries surpassed automobile collisions as the leading cause of death in US children. Annual automobile fatalities have decreased during 40 years through a multipronged approach. To develop similarly targeted public health interventions to reduce firearm fatalities, there is a critical need to first characterize firearm injuries and their outcomes at a granular level. We sought to compare firearm injuries, outcomes, and types of shooters at trauma centers in four pediatric health systems across the USA. Methods We retrospectively extracted data from each institution's trauma registry, paper and electronic health records. Study included all patients less than 19 years of age with a firearm injury between 2003 and 2018. Variables collected included demographics, intent, resources used, and emergency department and hospital disposition. Descriptive statistics were reported using medians and IQRs for continuous data and counts with percentages for categorical data. χ 2 test or Fisher's exact test was conducted for categorical comparisons. Results Our cohort (n=1008, median age 14 years) was predominantly black and male. During the study period, there was an overall increase in firearm injuries, driven primarily by increases in the South (S) site (β=0.11 (SE 0.02), p=<0.001) in the setting of stable rates in the West and decreasing rates in the Northeast and Mid-Atlantic sites (β=-0.15 (SE 0.04), p=0.002; β=-0.19 (SE0.04), p=0.001). Child age, race, insurance type, resource use, injury type, and shooter type all varied by regional site. Conclusion The incidence of firearm-related injuries seen at four sites during 15 years varied by site and region. The overall increase in firearm injuries was predominantly driven by the S site, where injuries were more often unintentional. This highlights the need for region-specific data to allow for the development of targeted interventions to impact the burden of injury. Level of Evidence: II, retrospective study