Markham () is a city in the York Region of Ontario, Canada. It is approximately 30 km (19 mi) northeast of Downtown Toronto. In the 2021 Census, Markham had a population of 338,503, which ranked it the largest in York Region, fourth largest in the Greater Toronto Area (GTA), and 16th largest in Canada.The city gained its name from the first Lieutenant-Governor of Upper Canada, John Graves Simcoe (in office 1791–1796), who named the area after his friend, William Markham, the Archbishop of York from 1776 to 1807.
Indigenous people lived in the area of present-day Markham for thousands of years before Europeans arrived in the area. The first European settlement in Markham occurred when William Berczy, a German artist and developer, led a group of approximately sixty-four German families to North America. While they planned to settle in New York, disputes over finances and land tenure led Berczy to negotiate with Simcoe for 26,000 ha (64,000 acres) in what would later become Markham Township in 1794. Since the 1970s, Markham rapidly shifted from being an agricultural community to an industrialized municipality due to urban sprawl from neighbouring Toronto. Markham changed its status from town to city on July 1, 2012.As of 2013, tertiary industry mainly drives Markham. As of 2010, "business services" employed the largest proportion of workers in Markham – nearly 22% of its labour force.
The city also has over 1,000 technology and life-sciences companies, with IBM as the city's largest employer. Several multinational companies have their Canadian headquarters in Markham, including: Honda Canada, Hyundai, Advanced Micro Devices,Johnson & Johnson, General Motors, Avaya, IBM, Motorola, Oracle, Toshiba, Toyota Financial Services, Huawei, Honeywell, General Electric and Scholastic Canada.