The first European to visit the area of the present-day Town of Slave Lake was David Thompson who explored the area in 1799. Following his brief visit, several fur trading posts were established around Slave Lake, with a Hudson's Bay Company post established at the mouth of the lake. The first community, called Sawridge, was renamed Slave Lake in 1923. It was wiped out by a flood in the 1930s, and was subsequently moved to its current location. It was incorporated as a town in 1965. The Town of Slave Lake was inundated by a flood of Sawridge Creek in July 1988.
2011 wildfire
On May 15, 2011, large parts of the town were affected by wildfires in the area. Winds pushed the flames into the town and destroyed many houses and businesses. Mandatory evacuation orders were issued, but with highways being closed, residents were urged to make their way to beaches, large parking lots, and open spaces. Highway 2 had been closed at the outset of the fire, but eventually re-opened for evacuation, with full evacuation ordered for Slave Lake. On May 16, 2011, provincial officials said that 40% of the town had been destroyed or damaged, including the town hall, the library, a radio station, a mall and a significant number of homes and other buildings; no injuries or deaths were reported. On May 17, 2011, Mayor Karina Pillay-Kinnee indicated one-third of the town had been destroyed by the wildfire. On May 20, 2011, a firefighting helicopter crashed into the Lesser Slave Lake near Canyon Creek where its pilot died at the scene. It crashed about off shore into water that was deep. On July 6, Prince William and Catherine, the Duke and Duchess of Cambridge, visited the town to offer encouragement to residents and support for rebuilding efforts.
In the 2016 Census of Population conducted by Statistics Canada, the Town of Slave Lake recorded a population of 6,651 living in 2,329 of its 2,762 total private dwellings, a change from its 2011 population of 6,782. With a land area of, it had a population density of in 2016. In the 2011 Census, the Town of Slave Lake had a population of 6,782 living in 2,294 of its 2,554 total dwellings, a 1.2% change from its 2006 population of 6,703. With a land area of, it had a population density of in 2011. The population of the Town of Slave Lake according to its 2007 municipal census was 7,031.
Sports
In 1994, the town hosted the Arctic Winter Games, which is a celebration of circumpolar sports and culture.