Documents in Law, History and Diplomacy contains materials from the 18th-21st centuries. This site ranges from colonial land grants to the 9/11 Commission report. There are treaties, a wealth of American primary sources and much more. One of the most useful features of this collection is the links between texts mentioned in the documents.
Resource URL: http://avalon.law.yale.edu/default.asp
Online Help: http://www.yale.edu/lawweb/avalon/help/helpdesk.htm