Anti-Federalism refers to a movement that opposed the creation of a stronger U.S. federal government and which later opposed the ratification of the Constitution

United States Constitution

The Constitution of the United States is the supreme law of the United States of America. It is the framework for the organization of the United States government and for the relationship of the federal government with the states, citizens, and all people within the United States.The first three...

 of 1787. The previous constitution, called the Articles of Confederation

Articles of Confederation

The Articles of Confederation, formally the Articles of Confederation and Perpetual Union, was an agreement among the 13 founding states that legally established the United States of America as a confederation of sovereign states and served as its first constitution...

, gave state governments more authority. Led by Patrick Henry

Patrick Henry

Patrick Henry was an orator and politician who led the movement for independence in Virginia in the 1770s. A Founding Father, he served as the first and sixth post-colonial Governor of Virginia from 1776 to 1779 and subsequently, from 1784 to 1786...

 of Virginia, Anti-Federalists worried, among other things, that the position of president, then a novelty, might evolve into a monarchy. A book titled "The Anti-Federalist Papers

Anti-Federalist Papers

The Anti-Federalist Papers are a collection of articles, written in opposition to the ratification of the 1787 United States Constitution. Unlike the Federalist Papers written in support of the Constitution, the authors of these articles, mostly operating under pen names, were not engaged in a...

" is a detailed explanation of American Anti-Federalist thought.
During the American Revolution

American Revolution

The American Revolution was the political upheaval during the last half of the 18th century in which thirteen colonies in North America joined together to break free from the British Empire, combining to become the United States of America...

 and its immediate aftermath the term "federal" was applied to any person who supported the colonial union and the government formed under the Articles of Confederation

Articles of Confederation

The Articles of Confederation, formally the Articles of Confederation and Perpetual Union, was an agreement among the 13 founding states that legally established the United States of America as a confederation of sovereign states and served as its first constitution...

.