Until the International Campaign to Save the Monuments of Nubia, the temple complex was located on Philae Island, near the expansive First Cataract of the Nile in Upper Egypt. These rapids and the surrounding area have been variously flooded since the initial construction of the Aswan Low Dam in 1902. The temple complex was dismantled and moved to nearby Agilkia Island as part of the UNESCO Nubia Campaign project, protecting this and other complexes before the 1970 completion of the Aswan High Dam. The hieroglyphic reliefs of the temple complex are being studied and published by the Philae Temple Text Project of the Austrian Academy of Sciences, Vienna (Institute OREA).
Philae is mentioned by numerous ancient writers, including Strabo,Diodorus Siculus, Ptolemy, Seneca, Pliny the Elder. It was, as the plural name indicates, the appellation of two small islands situated in latitude 24° north, just above the First Cataract near Aswan (Egyptian Swenet "Trade;" Ancient Greek: Συήνη). Groskurd computes the distance between these islands and Aswan at about 100 km (62 mi).

Despite being the smaller island, Philae proper was, from the numerous and picturesque ruins formerly there, the more interesting of the two. Before the inundation, it was not more than 380 metres (1,250 ft) long and about 120 metres (390 ft) broad. It is composed of syenite: its sides are steep and on their summits a lofty wall was built encompassing the island.

Since Philae was said to be one of the burying-places of Osiris, it was held in high reverence both by the Egyptians to the north and the Nubians (often referred to as "Ethiopians" in Greek) to the south. It was deemed profane for any but priests to dwell there and was accordingly sequestered and denominated "the Unapproachable" (Ancient Greek: ἄβατος). It was reported too that neither birds flew over it nor fish approached its shores. These indeed were the traditions of a remote period; since in the time of the Ptolemaic Kingdom, Philae was so much resorted to, partly by pilgrims to the tomb of Osiris, partly by persons on secular errands, that the priests petitioned Ptolemy VIII Physcon (170-117 BC) to prohibit public functionaries at least from coming there and living at their expense.

In the nineteenth century, William John Bankes took the Philae obelisk on which this petition was engraved to England. When its Egyptian hieroglyphs were compared with those of the Rosetta Stone, it threw great light upon the Egyptian consonantal alphabet.

The islands of Philae were not, however, merely sacerdotal abodes; they were the centres of commerce also between Meroë and Memphis. For the rapids of the cataracts were at most seasons impracticable, and the commodities exchanged between Egypt and Nubia were reciprocally landed and re-embarked at Syene and Philae.

The neighbouring granite quarries also attracted a numerous population of miners and stonemasons; and, for the convenience of this traffic, a gallery or road was formed in the rocks along the east bank of the Nile, portions of which are still extant.

Philae also was remarkable for the singular effects of light and shade resulting from its position near the Tropic of Cancer. As the sun approached its northern limit the shadows from the projecting cornices and moldings of the temples sink lower and lower down the plain surfaces of the walls, until, the sun having reached its highest altitude, the vertical walls are overspread with dark shadows, forming a striking contrast with the fierce light which illuminates all surrounding objects.