The sanctuary is not within the city itself, but is instead an example of an extraurban sacred site. There have been eight temples excavated at the site, dating from the Mycenaean to Archaic periods. This sanctuary is one of few to show consistent activity from the Bronze age up to the Roman period, although in the pre-archaic age the evidence for Artemis so-called is only the presence of aspects of the goddess which are consistent with the local nature goddess worshipped at the time. The site was first excavated from 1973-77, when remains of the temple were uncovered and investigated, and new digs were conducted as recently as 2010.
The final temple was built in 570 BC, and measured 44x18 metres and was a Doric peripteros with a single row of columns 14x6 around the outside. This building was destroyed in the invasion of the Persians in 480 BC. The cella of the temple included an adyton to house the cult statue. Adyta were common in architecture to denote special respect and protection given to powerful statues, and were found in sites associated with oracles, mysteries and healing incubation rituals. In Artemisions adyta were use to store sacred items.
The sanctuary included access to water, which was common at the goddess Artemis' sanctuaries. In the case of Hyampolis this was a deep well dug to an underground water source.
Although the sanctuary was established from the 12th century BC, the identity of the gods worshipped can be tracked through the archaeological record from the 9th century. The prevalence of jewellery finds in the 9th-8th century BC indicate that the sanctuary may at first have been dedicated to a singular feminine diety such as Artemis or Proto-Artemis, and only later hosted worship of the Phokian's Artemis Elephabolos (meaning Deer-Shooter). The change in the identity of the goddess can be traced in the occurrence of weapons in the archaeological record from the 7th-6th centuries, when weapons appear.
It is thought that Apollo of Abae (the oracle cult located in the city 8 kilometers from Hyampolis) was worshipped in conjunction with Artemis Elephabolos from the 9th century BC. Their names begin to appear in documents from the period, as well as tripods beginning to be deposited at the site.
An ash pile was uncovered at an early alter associated with the temple structure, indicating that the burning of bones involved with sacrifice took place from an early time in the history of the site. Pausanias 10.35.7 noted that cattle consecrated to Artemis grew up stronger and less affected by disease than other cattle, suggesting that the people of Phokis reared animals for sacrifice, particularly calfs and heifers in this instance, as was common practice in ancient Greece.
Finds varied over the continuous time that the site was active, which ranged from the 12th century BC when it was established into the Roman era. The earliest finds were primarily ceramics such as kraters, kylakes and cups used for feasting rituals. Also in the early archaeological record of the site are votive finds - particularly jewellery and bestial as well as anthropomorphic terracotta figures.
From the 9th century, these finds expand to include bronze tripods and jewellery. The associated tripods may also denote the inclusion of Apollo of Abae in worship at this site. By the 7th-6th century iron and bronze weapons are also dedicated, contributing to the theory that the identity of the sanctuary's goddess developed in this period to Artemis Deer-Shooter specifically, and by the mid-5th century jewellery ceases to be dedicated entirely.
The sanctuary hosted the annual Elephabolia, in which the Hyampolians celebrated their victory over the Thessalians. Although the Hyampolians honoured Artemis Elephabolos for their victory, sources do not suggest divine intervention on her part in the battle. It is thought that Artemis Elephabolos was chosen to receive honours for the event due to the liminal location of her sanctuary close to the area of Lokris, which overlooked the pass through which the Thessalian - and later the Persian, Macedonian and Roman - forces travelled. 
Rules and Regulations
According to Pausanias 10.35.7, the sanctuary at Hyampolis opened only twice a year and no more, which is why he did not see the cult statue himself.
The cult statue was kept in the adyton - an extra interior chamber with restricted access - within the temple compex, and was brought out only on occasion under the protection of ritual. Otherwise it was only accessible to the priestess of Artemis Elephabolos. 
It is theorised by McInerney (1999) that the site was significant to early Hyampolian community and functioned as the political core of Phokia, based on the finds of feasting ware from the 12th century before other political sites developed and fulfilled this function.
Who used the site, and where did they come from?
The visitors to the site most likely were people local to Hyampolis, since the cult of Artemis Elephabolos was particular to them, and the festival honouring her was strongly associated with the local history of Hyampolis' battle with the Thessalians.
Visitors will have also included travellers, since Pausanias recounts a visit there on his way to Boeotia (10.35.5-7). However, the temple itself only opened twice a year, so paying witness to the cult statue of the goddess would have been a more exclusive experience, and might have recquired prior knowledge of the local sacred calendar to achieve.
Budin, S.L (2015) Artemis (Routledge: London)
Cole, S.G (2004) Landscapes, Gender, and Ritual Space: The Ancient Greek Experience (University of California Press: London)
McInerney, J. (1999) The Folds of Parnassos: Land and ethnicity in ancient Phokis (University of Texas Press)
1 - Cole (2004) 200
2 - Ellinger (1987) 93
The remains of what is thought to be the sanctuary of Artemis Elephabolos is located in the city of Hyampolis in the east of the ancient region of Phocis, now in modern central Greece. It was about 8 kilometers from Abae, the town which hosted the oracular cult of Apollo Abae, a deity linked to the sanctuary of Artemis Elephabolos after the 9th century.
Hyampolis took its name from the Hyantes of Thebes, who fled there from Cadmus and his army, who expelled them over the border from Boeotia. Later the city was renamed Kalapodi, so the sanctuary can be termed Artemis Elephabolos of Kalapodi, but is still the same site.
Above: map of Greece including Hyampolis (here called Kalipodi).
Below: remains of the Sanctuary of Artemis Elephabolos.
Below: Layout of the sanctuary site. The temple includes the adyton to house the cult statue on the left end of the cella.