In Old Czech, the word kladno denoted a mature forest from which logs were obtained.

It lies in a mostly flat landscape of the Prague Plateau, albeit in the north the terrain becomes hillier.

The city limits contain two nature monuments: Žraločí zuby and Krnčí a Voleška.

[4] After the Bohemian branch of the Ždárský family died out in 1670, the town changed hands several times before it was bought by the Benedictine Břevnov Monastery in 1705.

[4] Bituminous coal was first discovered within the present city limits in 1775, but significant mining activity only started in 1850 and intensified over the following decades.

[8] The coal reserves began attracting the iron working industry, the largest of which eventually became the Poldi steelworks, founded in 1899.

[6] In 1870, Kladno was promoted to a city by Emperor Franz Joseph I, and in 1898 it was awarded the honorary title of "royal mining town".

In 1941, several surrounding municipalities (Kročehlavy, Rozdělov, Dubí, Dříň and Újezd) were annexed to Kladno.

For years, the city was home to the Poldi steel factory, the region's largest employer.

A number of companies has established production in Kladno, including Lego, NKT Cables, La Lorraine, Hanon Systems and Dr. Oetker.

The city is known as the home of many internationally known ice hockey players, such as Jaromír Jágr and Tomáš Plekanec.

Its ice hockey club, Rytíři Kladno, was successful in the past and is connected with many famous players of Czech ice hockey history, including 1998 Olympic gold medalists Jaromír Jágr, Pavel Patera, Martin Procházka, Libor Procházka and Milan Hnilička.

The city hosts various athletic events including the TNT – Fortuna Meeting in June, and the Kladno Marathon in September each year.

The Church of Saint Nicholas in Vrapice was a Romanesque rotunda from the early 13th century, rebuilt in the Gothic style around 1400.

[16] The Church of Saint Nicholas in Švermov, built in 1912–1913, is a mixture of Art Nouveau and Modernism.