Which agency is responsible for border security in the U.S.?

The responsibility for border security in the United States primarily falls to the U.S. Customs and Border Protection (CBP). This agency is tasked with enforcing laws related to customs and immigration and plays a key role in preventing illegal immigration, trafficking, and the entry of contraband. CBP is also responsible for processing travelers and goods entering the country and ensuring that borders are secure.

While the Department of Homeland Security (DHS) oversees CBP and other agencies involved in maintaining national security, including border security efforts, it is the CBP that directly manages the enforcement and operational aspects at the borders. The other agencies listed, like the FBI and NSA, focus on different areas of law enforcement and national security that do not include direct border protection responsibilities. Thus, CBP is recognized as the primary agency dedicated to border security functions.