From early in the 19th century, and particularly after the passage of the American Fugitives Slave Law in 1850, the towns along the Detroit River served as major terminals of the network of routes by which thousands of slaves reached Canada. Once in Canada the fugitives were often aided by philanthropic societies and individuals in securing land, employment and the necessaries of life. In some cases separate colonies were established for former slaves. By 1861 an estimated 30,000 fugitive blacks resided in Canada West, but more than a half of them returned to the United States following emancipation. *Note: This designation has been identified for review. A review can be triggered for one of the following reasons - outdated language or terminology, absence of a significant layer of history, factual errors, controversial beliefs and behaviour, or significant new knowledge.