On March 25, 2024, USDA announced unpasteurized, clinical samples of milk from sick cattle collected from two dairy farms in Kansas and one in Texas, as well as an oropharyngeal swab from another dairy in Texas, tested positive for highly pathogenic avian influenza (HPAI). USDA’s National Veterinary Services Laboratories confirmed the detection as HPAI H5N1 clade 2.3.4.4b, genotype B3.13. Phylogenetic analysis and epidemiology support a single introduction into this novel host followed by onward transmission. This report provides field epidemiologic summaries using data collected from epidemiologic questionnaires for H5N1 affected dairy herds.