In 1846, Windsor had a population of about 300. Two steamboats offered service to Detroit. The barracks were still manned. There were various types of tradesmen, a bank agency and a post office. The city's access to the Canada–US border made it a key stop for refugee slaves gaining freedom in the northern United States along the Underground Railroad. Many went across the Detroit River to Windsor to escape pursuit by slave catchers. There were estimated to be 20,000 to 30,000 African-American refugees who settled in Canada, with many settling in Essex County, Ontario.