Domains Critical to Homeland Security Act This bill authorizes the Department of Homeland Security (DHS) to conduct research and development to identify U.S. critical domains for economic and homeland security and evaluate the extent to which disruption, corruption, exploitation, or dysfunction of any such domain poses a substantial threat to homeland security. The bill defines United States critical domains for economic security as the critical infrastructure and other associated industries, technologies, and intellectual property, or any combination thereof, that are essential to U.S. economic security. DHS may conduct additional research into high-risk critical domains under specified circumstances.