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Minnesota State Law Library

Legal Research Topics

Sources of Law

What Constitutes "the Law"? 

Primary v. Secondary Sources

Legal resources are often divided into "primary" and "secondary" sources of law. Primary sources contain "the law" itself. Secondary sources are writings about the law. 

Primary sources come from the government. They are constitutions, statutes, regulations, and decisions of the courts. They can also be the charters and ordinances of municipalities (such as counties, cities, and towns), decisions of administrative agencies, and court rules. 

Secondary sources may be books, articles, annotations, or many other forms. They can be good places to begin research because they can provide background, explanation and vocabulary as well as references to the primary sources of law. 

For information on locating primary sources, please see the box labeled "Primary Law" below. To locate secondary sources, visit our subject guides, search the catalog, or ask a librarian for assistance. 

Mandatory Authority v. Persuasive Authority

Sources of law can also be divided into "mandatory" and "persuasive" authority. Mandatory authority is what a court must pay attention to when deciding a case. Only primary sources can be mandatory authority. For example, a Minnesota statute that applies to the case is mandatory authority in Minnesota. A Minnesota Supreme Court decision interpreting that statute would also be mandatory authority.

If no mandatory authority exists, courts may listen to persuasive authority but they are not required to follow it. Persuasive authority includes cases or laws from other jurisdictions and things like scholarly articles or books. 

Primary Law

Primary Sources of Minnesota Law

State Constitution

The Minnesota Constitution is the foundation document of Minnesota government. 

Legislative Law

Laws passed by the Minnesota Legislature are published annually as session laws in Laws of Minnesota. Laws passed by the legislature that are general in application and permanent in nature are arranged by subject and collected into the Minnesota Statutes. Budget laws appear in Laws of Minnesota but not Minnesota Statutes because they are in effect for only a limited period of time. A law vacating a state road would appear in Laws of Minnesota but not Minnesota Statutes because it applies only to a limited area. 

Minnesota Statutes is the official publication by the Minnesota Revisor of Statutes Office containing all statutes currently in force that have general application and continuing effect. 

Minnesota Statutes Annotated is an unofficial publication which contains the same statutes as Minnesota Statutes and also Notes of Decisions of the courts that have interpreted the statutes and other research aids.

In addition, local governments often pass ordinances affecting aspects of life in a county, city, or town. 

Executive Branch or Agency Law

Regulations issued by Minnesota's administrative agencies are published first in the State Register. This weekly publication also includes proposed regulations. All regulations currently in force are compiled in Minnesota Rules.


Opinions of the Minnesota Supreme Court and precedential opinions of the Court of Appeals are published in the Northwestern Reporter. Until 1977, Minnesota Supreme Court opinions were also published in Minnesota Reports. New opinions for the Court of Appeals and Supreme Court are released each week on the Judicial Branch website.

Primary Sources of Federal Law

U.S. Constitution

The United States Constitution is the supreme law of the land. 

Legislative Law

Laws passed by the United States Congress are first published as session laws in the Statutes at Large. Statutes that are currently in force and have general application and continuing effect are collected and arranged by subject in the United States Code

Administrative Law

Regulations issued by Federal administrative agencies are published first in the Federal Register. Published every business day, it also includes proposed regulations and other materials. All regulations currently in force are arranged by subject and compiled in the Code of Federal Regulations

Federal Courts

Decisions of the United States Supreme Court are published in the official United States Reports and in the unofficial Supreme Court Reporter and United States Reports, Lawyers' Edition

Federal appeals court decisions are published in the Federal Reporter. Since 2001, opinions that have not been selected for publication in the Federal Reporter can be found in West's Federal Appendix