As with other nearby settlements, the place name (originally Grouts) is of Slavic origin and means Gradec. It was first mentioned in 1209. The prime location of Greiz at the river Weiße Elster and the stream Göltzsch made it a fast growing town. It kept expanding during the last 1000 years. It has been recognized as town in the 13th century for the first time. Later the House of Reuss, a ruling German dynasty, built 2 castles in Greiz: the "Oberes Schloss" (Upper castle) and the "Unteres Schloss" (Lower castle). Both were built by famous architects and are still considered unique. Greiz became the capital of the Principality of Reuss-Greiz (until 1918).
Greiz has a large park in its center which is classified as an English garden. Its landscape is unique and well worth a visit. Thomasstraße, Burgstraße, Marktstraße, Waldstraße, and Leonhardtstraße with their Jugendstil houses are well known examples of that architectural style. In Prof.-Dr.-Friedrich-Schneider-Straße 4 there is one of the earliest examples of Art Deco architecture (built in 1911).
Greiz has a population of about 21,310 people (as of December 31, 2011).
In addition to a chemical works and a paper factory there are mechanical engineering operations, plastics manufacturing businesses, wood machining enterprises, medical technology, suppliers to the automobile industry, printing houses and breweries. In recent years various high tech businesses (sensor technology, climate simulators, micro-chip production) and environmental technology companies developed.
Adjacent cities include: