The Niagara District was a historic district in Upper Canada which existed until 1849. It was created in 1798 from the Home District and consisted of the counties of:
The district town, originally known as Newark, was renamed to Niagara and would later become Niagara-on-the-Lake.
In 1816, parts of this district and the Home District were separated to form the Gore District.
In 1845, a new Welland County was formed from Lincoln County.
In 1849, the district was replaced by the United Counties of Lincoln, Welland and Haldimand.