Born into slavery, in Port Tobacco, Charles County, Maryland, he escaped to Upper Canada (now Ontario) in 1830, and founded a settlement and laborer's school for other fugitive slaves at Dawn, near Dresden, in Kent County, Upper Canada, of Ontario.

Josiah Henson experienced hardships and sufferings at the hands of his masters as well, including having his arms broken and an injury to his back.

Riley would not regret his decision, for Henson rose in his owners' esteem, and was eventually entrusted as the supervisor of his master's farm, located in Montgomery County, Maryland (in what is now North Bethesda).

[3] Upon setting foot into Canada, Josiah Henson described the ecstatic feelings of liberation by throwing himself onto the ground and rejoicing with his family.

Josiah Henson first worked on farms near Fort Erie, then Waterloo Ontario, moving with friends to Colchester in 1834 to set up a Black settlement on rented land.

After earning enough, Henson was able to send his eldest son Tom to school, who in turn taught Josiah how to read.

[11] Through contacts and financial assistance there, he was able to purchase 200 acres (0.81 km2) in Dawn Township, in neighbouring Kent County, to realize his vision of a self-sufficient community.

The Dawn Settlement eventually reached a population of 500[citation needed] at its height, exporting black walnut lumber to the United States and Britain.

In 1838, Henson and the militia successfully captured the rebel ship Anne, cutting off their supply lines to southwestern Upper Canada.

Henson became the spiritual leader within the community and embarked on several trips to the United States and Great Britain where he met with Queen Victoria.

A federal plaque to him is located in the Henson family cemetery, next to Uncle Tom's Cabin Historic Site.

In 1991, a playwright was hired to create a drama based on Henson's Daviess County years; in the summer of 1993, Josiah was staged at the RiverPark Center in Owensboro and its six-night run drew more than 4,000 people.

After remaining in the hands of private owners for nearly two centuries, on January 6, 2006, the Montgomery Planning Board agreed to purchase the property and the acre of land on which it stands for $1,000,000 (~$1.45 million in 2023).

[23][24] In March 2009, the site received an additional $50,000 from the Maryland state Board of Public Works for the planning and design phase of a multiyear restoration project.

The Montgomery County park site (construction/restoration) reopened to the public on April 23, 2021, after the completion of the renovations and installation of new exhibits and building of the visitor center.