Johnsonburg is an unincorporated community and census-designated place (CDP)[10] located within Frelinghuysen Township in Warren County, in the U.S. state of New Jersey,[11] that was created as part of the 2010 United States Census.

An east-west route carried mail from Dover, New Jersey to Stroudsburg, Pennsylvania, and a north-south route carried mail from Albany, New York to Philadelphia, Pennsylvania.

Both routes crossed at right angles at this location, and a post office and tavern were built.

Johnsonburg had a post office, a large glove factory, and a "good local trade".

The railway was important to local dairy farmers, who shipped their products east to Newark and New York City.

[1][2] The 2010 United States census counted 101 people, 42 households, and 32 families in the CDP.

It was added to the National Register of Historic Places on October 15, 1992, for its significance in architecture, community development, commerce, industry, and religion.