Foreign Relations of the United States - From the Office of the Historian, "series presents the official documentary historical record of major U.S. foreign policy decisions and significant diplomatic activity."
From 1870-1976 - Beeghly owns in print Call Number: S 1.1
Online from 1945-1976: Office of the Historian
Online though incomplete from 1861-1960: University of Wisconsin Digital Collection
For full text of treaties before 1949:
Treaties and other international agreements of the United States of America, 1776-1949
Call Number: S 9.12/2: v. 1-13
For index of treaties, including after 1949:
Treaties in force : a list of treaties and other international acts of the United States in force on ..
Call Number: S 9.14: 2009
Also available online from US State Department
For full text of treaties after 1949:
United States treaties and other international agreements
Call Number: S 9.12
Treaties and Other International Acts Series
Call Number: S 9.10
*OWU does not possess a full collection of the above two resources. Be sure to check CONSORT for a complete listing.
Additional Guide to US Treaty Resources