The brooch was constructed from numerous individually made pieces; all of the borders and its terminals contain multiple panels holding multi-coloured studs, interlace patterns, filigree, and Celtic spirals.

The name by which it became known was chosen by its first commercial owner, the Dublin-based jeweler George Waterhouse, as a marketing ploy for selling copies during the height of the 19th century Celtic Revival.

The Tara brooch was likely made for a High King of Ireland or a dignitary or cleric, probably from the Kingdom of Brega, a branch of the Uí Néills, who ruled over much of today's Leinster.

[4] Instead, they were likely fixed in place by pushing the pin-shaft through the cloth, and fastened horizontally behind the head with stitches running through loops on the borders, and further secured by wrapping the chain around the pin.

[10][11] Depictions in illuminated manuscripts indicate that highly quality brooches were often placed over purple dye cloaks (brait in Gaelic)[12] just below the right shoulder.

Through 7th century trade and missionary contacts with Anglo-Saxon, Frankish and Lombardic cultures, Irish craftsmen developed sophistication in goldwork and adopted the style sometimes referred to by historians as "Hiberno-Saxon" or "late Celtic".

[n 3][15][16][17] In the late 19th century, the antiquarian Margaret Stokes was the first to observe that the use of trumpet spirals places it at least at the end of the so-called "Golden Age" of Insular art, given that the design had fallen out of use by 1050.

[18] Common elements between the Hunterston and Tara brooches and the Lindisfarne Gospels include curvilinear patterns and renderings of animal and birds in interlace.

[12] Whitfield has noted that Ireland was then relatively outward-looking and cosmopolitan – compared to the later Middle Ages – and that "it is not surprising that it should have produced jewels which reflected European fashions".

[24] It is bilaterally symmetrical[25] with a basic structure of a circular hook, semi-circular and linked terminals, a long pin and a string likely used for additional support to keep it in place against the wearers cloth.

[23][25] The complex geometry of its many designs and patterns include concentric and ancillary circles, rectangular inserts, and an outline likely planned with sketches made with a compass on parchment.

[9][23] The head (or "hoop" or "ring") is made from cast and gilt silver and is decorated on both sides using techniques and patterns influenced by the Iron Age La Tène style.

They are held in place by the then new technique of "jewellers' stitches" (also known as "bead settings" or "milli-graining"),[29] that is intricate and complex filigree patterns formed by minute bands of silver wire.

[4] Other decorative elements include cast depictions of animals (mostly thin-bodied fish) and abstract motifs, separated by glass studs, enamel, and amber.

The hoop and terminals are joined by silver grilled glass studs in red and blue that adopt contemporary Germanic garnet cloisonné techniques, and in part resemble those on the 8th-century Moylough Belt-Shrine and Ardagh Chalice (8 and 9th-centuries).

It is hinged to two ancillary panels with paired animal heads (which may be wolves or dragons) at the ends and two human faces formed from purple glass.

[36][37] The earliest surviving reproductions are two 1852 wood engravings which show it, according to Whitfield, "in near perfect condition" with the majority of the now missing filigree, studs, and inserted interlace designs intact.

[43] Waterhouse chose the brooch's name, deliberately but falsely linking it to the site associated with the High Kings of Ireland, "fully aware that this would feed the Irish middle-class fantasy of being descended from them".