Introduction: In asthma, neutrophil levels in sputum are correlated with disease severity and lung function, hence a better understanding of the genes and pathways that affect neutrophilic inflammation in these patients may offer new insights into disease pathogenesis. To identify genes that control neutrophilic inflammation, our lab applied a house dust mite model of asthma to incipient lines of the Collaborative Cross (CC). We identified a quantitative trait locus (QTL) for neutrophils and an associated chemokine, CXCL1, on Chr 7 and subsequently identified Zfp30 as a candidate gene. In aggregate, our results indicated that a Zfp30 cis-eQTL underlies variation in CXCL1 and neutrophil recruitment. However, the specific causal variant(s) remain to be identified. We sought to identify the causal variants that regulate Zfp30 expression level as a way to reveal important regulatory mechanisms of inflammation and disease-related phenotypes. Methods: Gateway cloning, luciferase assays, qPCR, and site-directed mutagenesis were used to clone candidate regulatory regions of Zfp30 from representative mouse strains and test the ability of these regions to recapitulate in vivo expression patterns. Results: We found that Zfp30 is differentially expressed in both CC lines and founder strains of the CC. Zfp30 expression levels in mice from the preCC correlate with the haplotype of the 5’ region of the gene, resulting in three expression groups (high, medium, and low). Using a combination of publically available SNP genotype data and DNAseI footprinting data, we identified a ~500 bp candidate regulatory region of the Zfp30 promoter which contains a single putative causal variant (rs51434084). Using reporter assays with haplotypes from representative CC strains, we show that this region of the Zfp30 promoter is sufficient to recapitulate in vivo patterns of expression at both the mRNA and protein level. Furthermore, mutagenesis of rs51434084 conferred a significant change in expression levels, successfully capturing the expression difference between high and medium Zfp30 expression groups. Conclusion: These results indicate that rs51434084 plays a significant role in the Zfp30 cis-eQTL and therefore likely affects CXCL1 levels and neutrophil chemotaxis. Future experiments will determine the mechanism of the variant’s impact on gene expression and characterize the mechanism by which ZFP30 regulates CXCL1 and other targets.