Situated away from the sea and well-protected from pirates, this area was inhabited by Illyrians, and from the Roman times, an inscription was found. The XVIth century parish church of Sveti Martin is situated on the hill of Mratinovo; it is a favorite spot for walkers and is known for its church tower surrounded by ancient pine trees. Sveti Roko's Church in Postrana also commands a nice view from its big round stone terrace with very old "kostili" trees. The church of Sveti Vid is the oldest church in Zrnovo and one of the oldest in the region (around 1300).
The traditional, Mostra is performed in front of this church, as are other local festivities. Another item of interest in Zrnovo is the great number of Dalmatian stone boundary-walls "meje" which support the terraced vineyards. One of the bestknown and best-preserved "Kastel" in Zrnovo is in Postrana; it belonged to the respected diplomat Jakov Banicevic (1466-1532), a friend of Erazmus of Rotterdam. Jakov Banicevic (Jacobus de Bannisis) was born on October 15 1466. He was a great European diplomat, counsellor and the envoy of the emperors Maximillian I and Charles V, the friend of Erasmus from Rotterdam, Albrecht Dürer, Pietro Bemba; he died in Trento on December 19 1532. The memorial plaque was put on his native house in 1646. Erasmus from Rotterdam said about this man: "He is the man honoured by numerous various abilities". The best known man from Zrnovo today is the great Croatian writer Petar Segedin, who described his native Zrnovo in numerous pages of his rich work.
The inhabitants of Zrnovo, from ancient times until today, were skilled and talented craftsmen, especially stonecutters and builders. But they never abandoned their fields, on which most of all cultures, they would cultivate vineyards; from them, they would make the intoxicating wine PLAVAC. To the visitor of today, especially interesting are the terracelike stone walls which enclosed the stingy soil that nourished this ancient Mediterranean culture. The cove under these vineyard terraces on the southern side of the Island of Korcula today is available to the more persistent tourists. The Zrnovo inhabitants gave them the mutual name "defora", while in the navigational maps they are recorded as: Orlandusa, Gostinja Vala, Rasohatica, Pavja Luka.
Not far from the Zrnovo hamlet of Brdo above the cove of Vrbovica lies Kocije. an area of chalk dolomites of various forms with a fresh water well. This is a very attractive excursion point and is easily accessible.

Mjesto Žrnovo je najbliže gradu Korčuli, udaljeno svega 4 km glavnom cestom na putu prema unutrašnjosti otoka. Smješteno je u slikovitom predjelu okruženom brežuljcima, vitkim čempresima i drugim terasastim kamenim ogradama, vinogradima i maslinicima; cijeli krajolik okićen je dolomitnim stijenama,  što na ovom prostoru poprima fantastične oblike.
U zapisima arheoloških publikacija o prvim počecima života na otoku Korčuli iz pretpovjesnog i kasnijeg vremena, dosta se spominje područje Žrnova. U Jakasovoj špilji nađeni su tragovi i predmeti iz mlađeg kamenog doba, zatim kamene sjekire u okolici Brda, a otkriveno je i više ilirskih gomila (u blizini mjesnog groblja Sv. Vid).
Od kulturno-povijesnih spomenika vrijedno je spomenuti u Prvom Selu crkvicu Sv. Mihovila, koja se spominje u ispravi iz 1329. god., a obnovio ju je Jakov Baničević mlađi, početkom XVI st., zatim ladanjske kuće i kašteli korčulanskih obitelji Dimitri i Boschi te kuća obitelji Brčić-Muko, s kapelicom (natpis iz 1770. god.)
U Postrani se osobito ističu stari kašteli Nikole Didovića Antića, Ivana Curaća Fedelice, te kaštel koji je nekada pripadao obitelji Baničević, a do njega je i rodna kuća istaknutog diplomate i ličnosti poznate u evropskim političkim i kulturnim zbivanjima prve polovice XVI st. - Jakova Baničevića starijeg, crkvenog dostojanstvenika, humaniste i tajnika cara Maksimilijana.
U Žrnovu je uvijek bilo vrsnih zanatlija, posebice kamenoklesara i zidara.Poljoprivredna proizvodnja predstavljala je važnu aktivnost, a na vinorodnim područjima prisojne strane Defora, na škrtoj zemlji terasastih dolaca, od davnine kao i danas, uzgaja se loza plavac, od čijih se plodova proizvodi odlično crno vino.
Posljednjih dvadesetak godina Žrnovo postaje i turističko mjesto, posebice njegov sjeverni i južni dio, koji obiluju prekrasnim iskonskim skrovitim mjestima, uvalama i plažama. Samo mjesto, nudi posebne užitke u razgledavanju starih kamenih zdanja, dvora, volata i drugih lako prepoznatljivih posebnosti.
Žrnovo je za turiste zanimljivo i po velikom broju kamenih meja koje oivičuju polja vinove loze i drugih poljoprivrednih kultura. Nedaleko od zaseoka Brdo iznad uvale Vrbovica nalazi se Kočje, gromade dolomita kredne formacije najrazličitijih oblika, s izvorom pitke vode. To je vrlo privlačan izletnički punkt, do kojeg se relativno lako dođe uskim stazama kroz makiju.
Među najpoznatijim Žrnovcima današnjeg doba je svakako veliki hrvatski književnik Petar Šegedin, koji je svoj rodni kraj prikazao na brojnim najboljim stranicama svoga bogatog opusa.