At the turn of the twentieth century, hydroelectric power development along the Niagara River rapidly transformed the Town and Village of Niagara Falls, Ontario into an industrial city. The community changed demographically as well, with large numbers of foreign immigrants arriving to work both on the massive construction projects and in the factories which were drawn to the area due to the availability of inexpensive power. In 1891, the area later incorporated into the City of Niagara Falls was overwhelmingly composed of inhabitants of British origin, but by 1911, roughly 14% of the residents originated from Southern and Eastern Europe. This paper examines the demographic transformation of Niagara Falls during this time, constructing a profile of the immigrant population using census data from 1891, 1901 and 1911. The census data reveal where distinct ethnic communities were located, as well as their composition, providing a groundwork for further exploration of the integration process of this relatively large number of "foreigners" into the British-Canadian resident population. Some segregation was imposed, as in the case of single male construction labourers, other segregation was voluntary, such as Italian immigrants forming their own distinct neighbourhood. Many Southern and Eastern European immigrants faced racial discrimination in one form or another, from institutions such as the police department, local newspapers and employers, as well as from citizens groups such as The Lord Day Alliance. This study addresses the relative silence of the historiographical record regarding this influx of new Canadians to this area at the turn of the twentieth century, and the many challenges which they faced.