The recent expansion of HPAIV H5N1 infections in terrestrial mammals in the Americas, most recently including the outbreak in dairy cattle, emphasizes the critical need for better epidemiological monitoring of zoonotic diseases. In this work, we detected, isolated and characterized the HPAIV H5N1 from environmental swab samples collected from a dairy farm in the state of Kansas (USA). Genomic sequencing of these samples uncovered two distinctive mutations in the PB2 (E249G) and NS1 (R21Q) genes which are rare and absent in recent 2024 isolates of H5N1 circulating in the mammalian avian species. Additionally, approximately 1.7% of the sequence reads indicated a PB2 (E627K) mutation, commonly associated with the virus´s adaptation to mammalian hosts. Phylogenetic analyses of the PB2 and NS genes demonstrated more genetic identity between this environmental isolate and the 2024 human isolate (A/Texas/37/2024) of H5N1. Conversely, HA and NA gene analyses revealed a closer relationship between our isolates and those found in other dairy cattle with almost 100% identity, sharing a common phylogenetic subtree. These findings underscore the rapid evolutionary progression of HPAIV H5N1 among dairy cattle and reinforces the need for more epidemiological monitoring which can easily be done using environmental sampling.