No one knows for certain how many interest groups there are in the United States. But few experts deny that the number is enormous. In Washington alone, there are perhaps as many as 15-20,000 interest groups.1 Outside of Washington, in states and localities across the country, the number of interest groups is probably over 200,000.2 These numbers seem large because they are. There is a general consensus among interest group experts that there are more interest groups in the United States today than at any time in American history.3