The Departments of Commerce, State and Treasury are the primary agencies in charged with the implementation and enforcement of export regulations. Each of the Departments is responsible for different areas of exports, though there are times when jurisdiction may overlap. The Department of Commerce regulates the export of items and information that have civil applications, the Department of State regulates the export of items that have military applications or that relate to space, and the Department of the Treasury enforces country-specific embargoes and financial sanctions on individuals, organizations and countries.
More information from these agencies can be found through the links below.