Unionville’s first residents were settlers of German origin who emigrated here from the United States in 1794. This group was initially led by Wliiam Berczy and consisted of sixty-four families whose pioneer efforts were instrumental in the founding of many of Markham’s first communities. The Unionville branch of these pioneers was led by Philip Eckhardt whose family were instrumental in the formation of Unionville. Sometime in the 1830s, Eckhardt built a flour mill, called “Union Mills” that was constructed along the bank of the Bruce Creek, one of many tributaries of the Rouge River.

As the Union mill grew so did the surrounding hamlet. Soon the hamlet became a village and in 1851 a post office opened. Not suprisingly the post office was officially named Unionville. Eckhardt’s grandson William, was determined to see Unionville grow and laid out the first plan of subdivision for the area. In 1871 William Berczy was instrumental in Unionville’s inclusion as a stop on the Toronto and Nippissing Railway line. This led to further expansion and growth for the Village of Unionville.

The Stiver family also play a prominent role in the history of Unionville. The Stivers were involved in building many of Unionville’s heritage houses still standing in Unionville They also built the Stiver Mill on Station Lane in the early 1900. Today, this Mill complex is an important part of Unionville’s cultural programs and community events and a frequented stop by tourists who marvel at this restored milling operation that stands out with its bright red fascade that transports onlookers back to Unionville’s rural roots and a far cry from the bustling urban metropolis that has sprung up on its doorstep.