Lahij is a village and municipality on the southern slopes of Greater Caucasus in Azerbaijan. Population is approximately 860 people who speak the Tat language.
Lahij is a notable place in Azerbaijan, with its authentic handicrafts traditions, particularly related to copper. The village's carpet and rug crafts are also well known in Azerbaijan and the South Caucasus. Lahij has an old sewage system (some experts claim that it was built 1000 – 1500 years ago). Due to frequent earthquakes local people have developed sophisticated and authentic construction techniques.
The majority of the population of Lahij speaks the Tati language. The residents of the region are usually bilingual: as well as the Tati language, an Iranian language, the Azerbaijani language is also widely spoken.
Being situated on the left bank of the River Ghirdiman and the slopes of the Niyal Mountain Chain, the settlement of Lahij is a unique living district, with its unusual planning lay out, transport systems, and its public, private and religious buildings. Lahij is an example of early urbanization and architecture, as shown by its cobbled streets and squares, together with its developed sewerage systems and water pipelines. Subterranean kurabandis (‘sewerage system’), made from river stones, and dating back to almost one thousand years, are thought to be one of the most ancient sewerage systems used in the world.