It is the site of the 1257 Battle of Frechen between Conrad von Hochstaden, Archbishop of Cologne and the people of the town. In the 16th century it acquired a name for its terra cotta artifacts, especially the "Bartmannskrug" (beardman jug). Later in the 18th century lignite was first industrially mined. Digging for lignite dominated the city's economy until the end of the 20th century. In 1891 the first briquette factory was opened. On 2 September 1951 Frechen received its city-rights including the villages of Bachem, Hücheln and Buschbell. On 1 January 1975 the nearby villages of Grefrath, Habbelrath, Königsdorf and Neufreimersdorf were also incorporated.
As of January 31, 2008 there were 51.387 inhabitants registered.