In 1823, discussions began to build a courthouse and jail in L'Orignal for the District of Ottawa. Jacob Marston, a prominent local man, donated two acres of land for the construction.

In 1825, a beautiful stone building in the classical Loyalist Revival style opened. It was enlarged several times, notably in 1850 with the west wing and in 1862 with the east wing.

In 1962, the administrative offices of the United Counties of Prescott and Russell were added to the edifice. The oldest prison in Ontario closed its doors in 1998, but the second floor remains occupied by the courthouse.

With its beautiful dome and orange roof, this unique building is one of the most significant for L'Orignal, now part of Champlain municipality. The importance of this heritage complex goes beyond the borders of the United Counties of Prescott and Russell. It is the oldest surviving courthouse in Ontario and one of the few examples of an establishment that housed local government before the Municipal Act of 1849.

To this day, it remains a privileged witness to all the stages affecting regional government.