Market town in Central Italy, (province of Ancona, Marche region) in the Esino valley. Sometimes spelt Iesi by non-residents - J is not a generally used letter in Italian.
Best known local product is the pleasant white wine Verdicchio dei Castelli di Jesi, sold in amphora-shaped bottles - a successful 1960s marketing wheeze. Some local producers are now experimenting with a wider range of grape varieties. The other obscure local DOC - Dolcetto di Morro d'Alba - is generally well worth avoiding, but makes a good fortified wine available in unmarked bottles if you know the right peasants.
Birthplace of the composer Pergolesi and (somewhat apocryphally) of the Holy Roman Emperor Frederick II, whose somewhat elderly mother Constance supposedly gave birth in public in the town square (now Piazza Federico II, surprise surprise) in order to prove that there was no trickery involved.
Worth seeing: the walled centro storico, including the cathedral and the Palazzo della Signoria; the town art gallery (pinacoteca) has quite a good collection or works by Lorenzo Lotto. Smartest bar is Bardi on the Corso; best ice cream at Tuttogelato on Viale della Vittoria; pizze from Settimo Cielo on via Gramsci. The imposing (for a small town) theatre runs a short season of opera annually and a few other events. Accommodation not prolific: the soulless Federico II (expensive) and Albergo dei Nani (moderate) are on the main road towards Ancona and the industrial area; the (not that cheap) Italia by the station is pleasant enough and has a good restaurant, and the (least expensive) Mariani in the centre was a bit of a dive in 1990 but may have improved.
Like small towns everywhere, Jesi is generally considered by all local inhabitants aged under 25 to be the most boring place in the universe. Even the anarchists go home to dinner with mother after the passeggiata at 8 pm on the dot. However, to the outsider it can be seen as a consummate piece of "real Italy", flourishing amongst largely ignored historic buildings that would be regarded as national treasures elsewhere.
Jesi is on the main(ish) east-west railway line from Rome to Ancona, and close to Ancona airport (a cheap RyanAir destination for residents of the British Isles).