Kingston is a city in Ontario, Canada, on the northeastern end of Lake Ontario. It is at the beginning of the St. Lawrence River and at the mouth of the Cataraqui River, the south end of the Rideau Canal. Kingston is near the Thousand Islands, a tourist region to the east, and the Prince Edward County tourist region to the west. Kingston is nicknamed the "Limestone City" because it has many heritage buildings constructed using local limestone.

Growing European exploration in the 17th century and the desire for the Europeans to establish a presence close to local Native occupants to control trade led to the founding of a French trading post and military fort at a site known as "Cataraqui" (generally pronounced /kætəˈrɒkweɪ/ ka-tə-ROK-way) in 1673. The outpost, called Fort Cataraqui, and later Fort Frontenac, became a focus for settlement. After the Conquest of New France (1759–1763), the site of Kingston was relinquished to the British. Cataraqui was renamed Kingston after the British took possession of the fort, and Loyalists began settling the region in the 1780s.

Kingston was named the first capital of the United Province of Canada on February 10, 1841. While its time as a capital city was short and ended in 1844, the community has remained an important military installation. The city is a regional centre of education and health care, being home to a major university, a large vocational college, and three major hospitals.

Kingston was the county seat of Frontenac County until 1998. Kingston is now a separate municipality from the County of Frontenac. Kingston is the largest municipality in southeastern Ontario and Ontario's 10th largest metropolitan area. John A. Macdonald, the first prime minister of Canada, lived in Kingston.

Cataraqui, Kingston's original name, is a derivation of an Indigenous language name for the Kingston area. The word may mean "Great Meeting Place", "the place where one hides", "impregnable", "muddy river", "place of retreat", "clay bank rising out of the water", "where the rivers and lake meet", "rocks standing in water", or "place where the limestone (or clay) is".

Cataraqui was referred to as "the King's Town" or "King's Town" by 1787, in honour of King George III. The name was abbreviated to "Kingston" in 1788. Cataraqui today is an area around the intersection of Princess Street and Sydenham Road, where the village of Cataraqui (formerly known as Waterloo) was located. Cataraqui is also the name of a municipal electoral district.

Archaeological evidence suggests people lived in the Kingston region as early as the Archaic period (about 9,000–3,000 years ago). Evidence of Late Woodland Period (about 500–1000 AD) early Iroquois occupation also exists. The first more permanent encampments by Indigenous people in the Kingston area began about 900 AD. The group that first occupied the area before the arrival of the French was probably the Wyandot people (Hurons), who were later displaced by Iroquoian groups.

At the time the French arrived in the Kingston area, Five Nations Iroquois (Haudenosaunee) had settled along the north shore of Lake Ontario. Although the area around the south end of the Cataraqui River was often visited by Iroquois and other groups, Iroquois settlement at this location only began after the French established their outpost. By 1700, the north shore Iroquois had moved south, and the area once occupied by the Iroquois (which includes Kingston) became occupied by the Mississaugas, a subtribe of the Anishinaabe, who had moved south from the Lake Huron and Lake Simcoe regions.