There are many strategies for finding relevant US government resources. As stated above, a great starting point is the UCSD US Government Information Research Guide. The databases, websites, and print guides/indexes listed below are also excellent. Several of these resources will help you identify specific publications (with call numbers that you can browse around to find more) that will have information on your topic. Finally, you can simply go to the shelves with print documents (Geisel 2W) and browse by call number. In order to find out which call number to browse in, you need to understand that US government documents and publications are organized by the Superintendent of Documents (SuDocs) Classification Scheme, which is based on US government agencies. In order to see how these classification numbers are structured and to identify the abbreviations (stems of the classification numbers) have been assigned to different agencies, see this tutorial you can use this provided by the US Federal Depository Library Program.
Please note that I have listed the following resources are in order of my own preference (mostly because of ease of searching), but all are very important.
Congressional sources provide information on virtually every topic imaginable, including any topic in foreign relations or in another country with which the US government was/is concerned. Congressional Research Service (CRS) reports are often excellent starting points for research topics, because these are studies carried out by subject experts at the Library of Congress for government employees and members of congress, and included excellent summaries and bibliographies.
An independent non-governmental research institute and library located at The George Washington University, collects and publishes declassified documents obtained through the Freedom of Information Act. It provides the most comprehensive collection available of significant primary documents central to US foreign and military policy since 1945. UCSD LIbrary also subscribes to its supplementary database, the Digital National Security Archive which provides additional information.
U.S. Declassified Documents Online 
Full text of documents from various government agencies: the White House, the CIA, the FBI, the State Department and others, declassified by the U.S. government, and obtained from Presidential Libraries.
Digital National Security Archive
Provides access to nearly 40,000 declassifed government documents from 1945 to present, organized into collections, each focused on a single topic. See also the National Security Archive website, which provides access to additional documents and information.
Foreign Relations of the United States
Official diplomatic record of U.S. relations with other countries. Contains important speeches, communiques, and other communications of State Department officials and diplomats. There is a delay (approximately 30-40 years) in the release of information as it becomes declassified.
Reports from U.S. Diplomats stationed in particular Latin American Countries, Including:
The Confidential U.S. State Department Central Files for Mexico can be found in Proquest History Vault (scroll down to the "International Relations & Military Conflicts Module" to find the "Confidential U.S. State Department Central Files for Europe and Latin America, 1960-1969")
[Latin America] Confidential Print: Latin America, 1833-1969
The documents of Confidential Print: Latin America are full text records of the British Foreign Office covering the whole of South and Central America, plus the non-British islands of the Caribbean, from just after the final Spanish withdrawal from mainland America in the 1820s to the height of the Cold War in the 1960s.
[Latin America] Confidential Print: North America, 1824-1961
This collection consists of the Confidential Print for the United States, Canada and the English-speaking Caribbean, with some coverage of Central and South America.
Catalog of US Government Documents
Keyword Searchable Online Index to Government Documents Provided by the U.S. Government
Federal Digital System (FDsys)
GPO's Federal Digital System (FDsys) provides public access to Government information submitted by Congress and Federal agencies. It includes the content previously available in GPO Access and more.
Guide to Federal Records in the National Archives of the United States
1995 Print Version available in :
US Docs, Geisel Floor2 West AE 1.108:G 94 (3 vol.)
The index to this guide is very helpful in identifying relevant collections in microfilm and other formats which can be used at the Archives themselves, or, in many cases, at other libraries. UCSD holds some of these and many others can borrowed through inter-library loan. Such holdings include copies of many collections from foreign archives.
US Government Documents Registry
Online, Keyword-Searchable Index to Government Documents Provided by the Haithi Trust
Historical Statistics of the United States
Although this ebook draws on various sources of information, government information, government resources comprise a significant portion of these.
Excellent starting point to identifying and accessing government resources.
Mexican Republic (Federal) Government Website
Click on "Dependencias" to get to
Official Website for Chamber of Deputies in Mexico
Official Website for Senate in Mexico
Official Website for Mexican Supreme Court
Official Website for Presidency of the Republic of Mexico
An excellent portal to many Latin American government resources is LANIC's Government Link (on its homepage). You can explore Latin American government websites by country, subject, branch (i.e. Law & Justice, Military, Political Parties), etc.
Instituto Nacional de Estadistica y Geografia (Mexico)
Provides Access to Contemporary and Historical Mexican Census Data
Latin American Government Documents Archive (LAGDA)
Web-archiving service capturing ministries and presidents of 18 Latin American countries. Compiled by the University of Texas at Austin.
Political Database of the Americas
Extensive information about political systems, constitutions, electoral data, political parties, indigenous peoples, democracy and political participation in most Latin American countries. Maintained at Georgetown University.
Presidential Messages -- Argentina and Mexico
Contains digital images of Mexican and Argentinian presidential speeches from the early 19th century to the present. Compiled by the Latin American Research Resources Project of the Center for Research Libraries.
Human Rights Organizations
Inter-American Development Bank (IDB)
International Labor Organization (ILO)
International Monetary Fund (IMF)
World Health Organization (WHO)
World Trade Organization (WTO)
Confidential Print: Latin America, 1833-1969
The documents of Confidential Print: Latin America are full text records of the British Foreign Office covering the whole of South and Central America, plus the non-British islands of the Caribbean, from just after the final Spanish withdrawal from mainland America in the 1820s to the height of the Cold War in the 1960s. The series originated out of a need to preserve the most important papers generated by the Foreign and Colonial Offices. These range from single-page letters or telegrams to comprehensive dispatches, investigative reports and texts of treaties. All items marked ‘Confidential Print’ were printed and circulated immediately to leading officials in the Foreign Office, to the Cabinet, and to heads of British missions abroad.
Selected Bibliography of US Government and International Documents on Latin America and the Caribbean
Maintained by the American Library Association's Government Document's Round Table
UCSD's U.S. Government Information Research Guide
This provides a great introduction to major access points and strategies to find U.S. government resources.
This guide organizes resources into US, California, International, Local and Municipal and other categories (such as the History of Law). The International Law tab is particularly useful for finding information about Latin American Law (including accessing the laws themselves).
Pages with Resources by Theme on this guide -- including:
There are several resources held by UCSD Library and beyond which contain Latin American Census Material. These include:
1. The Family Search Digital Library, provided by the Church of Jesus Christ of Latter Day Saints in Salt Lake City, is increasingly digitizing its microflm materials to make them freely accessible available online.
To search for and access material for a particular region, create an account and go to the Family Search Research Wiki.
Use the Map or "Search by Place and Topic" box. This will bring you to a country specific page where you can search for a more specific term or use the facet menu on the right to identify particular kinds of records and collections (church, census, etc.)
For example, to get to Mexico's first census (the Padrones, gathered between 1752-1865) as well as additional Mexican Census Material:
From the Famiy Search Research Wiki
> Search for Mexico, which will take you to the Mexico Genealogy Page
> Click on "Census" under record type on the left (Please note that you can also search for other formats and collections of vital statistics) OR Search for Padrones
(Either search brings you to the Mexico Census Page)
> Scroll down and click on: Padrones, 1752-1865
> Scroll down and click on the camera icon to the right of the documents you want to consult
2. The UCSD Library has purchased Datasets for relatively recent censuses in a number of Latin American Countries
Brazil 2010, Population Census, GCA-GIS
Chile 2017, Population Census, GCA-GIS
El Salvador 2007, Population Census, GCA-GIS
Guatemala 2018, Population Census, GCA-GIS
Honduras 2013, Population Census, GCA-GIS
Mexico, 2010, Population Census, GCA-GIS
All of these can be found in the "Latin American Census Collection" and accessed with AD login on the X: drive in the GIS Lab.
3. National Centers of Statistics and Geographical information (such as Mexico's Instituto Nacional de Informacion Estadistica y Geografica: INEGI) hold a wide range of census materials
