Federal Agencies in WY Federal Agencies operating within WY. Federal Agencies in WY Bureau of ATF Cheyenne, Laramie County Federal Emergency Mgmt Agency Cheyenne, Laramie County Homeland Security Investigations (HSI) Casper, Natrona County Homeland Security Investigations (HSI) Cheyenne, Laramie County Internal Revenue Service Cheyenne, Laramie County US Marshals Service Cheyenne, Laramie County
