It was a dark and forbidding land of windswept mountains and badlands.
- Plateau of Thay • First Escarpment • Second Escarpment
- Thaymount • Sunrise Mountains
- Wizards' Reach • Alamber Sea
- Lake Thaylambar
- River Lapendrar • River Thay • River of the Dawn • River Umber • River Thazarim
Prior to Szass Tam's elevation to supreme ruler of Thay, the land was ruled by a council of eight powerful mages known as Zulkirs, each of whom specialized in a different school of magic. During the chaos of the Spellplague, Szass Tam named himself regent and eventually became the one true power in Thay. The zulkirs thereafter served as Szass Tam's vassals.
The tharchs were the eleven regions of Thay, each ruled by a separate tharchion.
- Alaor: ruled by Tharchion Thessaloni Canos
- Delhumide: ruled by Tharchion Invarri Metron
- Eltabbar: ruled by Tharchion Dmitra Flass, also made Zulkir of Illusion sometime between 1375 DR and 1385 DR
- Gauros: ruled by Tharchion Azhir Kren
- Lapendrar: ruled by Tharchion Eseldra Yeth since the death of Hezass Nymar in 1385 DR.
- Priador: this tharchion position was vacant since Aznar Thrul was murdered in 1375 DR
- Pyarados: ruled by Tharchion Nymia Focar
- Surthay: ruled by Tharchion Homen Odesseiron
- Thaymount: ruled by Tharchion Pyras Autorian
- Thazalhar: this tharchion position was vacant since Milsantos Daramos died in 1382 DR of old age.
- Tyraturos: ruled by Tharchion Dimon, also a priest of Bane
The nation relied heavily on slavery, a practice heavily frowned upon by nations throughout northern and northwestern Faerûn. In Thay itself, the zulkirs and other prominent Red Wizards grew rich beyond imagination from this sinister trade. From their strongholds and estates, they used this wealth to constantly scheme and plot for mercantile and military domination of neighboring nations.
Slavery was a common branch of trade in Thay. Slave markets were restocked with war prisoners, conquered Rashemi, or people who were sold into slavery. While folk of Mulan descent removed all body hair (at least on the head) and Rashemi freemen at least clipped their hair short, slaves were not allowed to cut their hair at all. They could be easily distinguished by the heavy and filthy mass of hair they wore.
Slaves were used in warfare, where they were given sandal-boots, spears, headscarves, loincloths, and—if they were lucky—a baldric hung with waterskins. 
The soldiers of Thay wore armor of mirror-bright silver to give off blinding reflections (but also had white cloth slipcovers to prevent heating and betraying location.)
The nation of Thay came about when a sect, calling itself the Red Wizards, declared its freedom from the god kings of Mulhorand. The sect's center of strength was in the northern provinces where the natives did not have the inbred reverence for the god-kings. After razing the city of Delhumide they declared themselves the free nation of Thay in 922 DR. Since then Mulhorand defended itself, quite successfully, against two invasions from Thay.
The armies of Thay marched on Aglarond and Rashemen many times and folk feared that the time would soon come when the zulkirs mobilized again. On the other hand, few invasions ever overcame the great mountains girding the Plateau of Thay, and the secretive and suspicious Red Wizards raised barriers just as formidable to discourage travelers from venturing into their lands.
In 1375 DR, Szass Tam set in motion a series of events such as the murder of the zulkirs of transmutation, Druxus Rhym, and evocation, Aznar Thrul; crafting an undead army with the atropal Xingax from the bodies of slaves and prisoners of war; and portraying a failed unauthorized Thayan invasion on a Rashemi town by the Tharchions Azhir Kren and Homen Odesseiron as a Rashemi invasion onto Thayan soil stopped by the great casualties of Thayan soldiers and his "timely" rescue of the invading force. All of these actions created a climate of fear within the nation of the Red Wizards and endeared him to the people as a savior who could end the country's woes.
His plot was uncovered by his former confidant, Dmitra Flass, who put the puzzle together and alerted the remaining zulkirs, obviously excluding the lich. When Szass Tam proposed to make himself "temporary regent" to end all the suffering of the nation and crush the undead forces and other such troubles, the five of the six zulkirs voted against his proposition with only Yaphyll, Zulkir of Divination, abstaining from the vote. Szass Tam immediately had the Order of Necromancy under his control alert the common folk that the beloved hero of Thay had been denied from ending their suffering. Riots erupted in the streets, which he also used to his advantage, taking control over garrison commanders and summoning demons to kill the rioters. The appearance of the demons did nothing to behoove the reputation of Nevron's Order of Conjuration, as they believed his servant had summoned the demons to fight. Szass Tam appeared all over the city to quell the fighting, endearing him to the people even more.
Soon afterword, much of the undead force had been destroyed and the nighthaunt and angel of decay leaders had been obliterated along with much of the Burning Braziers, the latter thanks to the rigged magical torches he had given them. Szass Tam openly declared himself ruler of all Thay, thus declaring war against the remaining zulkirs of Thay. Hell had come to Thay.
Thayans believed that the gods sent luck to the strong and resolute, not to the gentle and compassionate.
- Burning Braziers
- Black Flame Zealots
- Brothers and Sisters of the Pure Flame
- Order of the Salamander
- ↑ Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast). ISBN 0-7869-1836-5.
- ↑ John Terra (February 1995). The Moonsea (Reference Guide). (TSR, Inc), p. 54. ISBN 978-0786900923.
- ↑ 3.0 3.1 3.2 3.3 Bruce R. Cordell, Ed Greenwood, Chris Sims (August 2008). Forgotten Realms Campaign Guide. (Wizards of the Coast), p. 180. ISBN 978-0-7869-4924-3.
- ↑ Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast), p. 206. ISBN 0-7869-1836-5.
- ↑ 5.0 5.1 Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast), p. 207. ISBN 0-7869-1836-5.
- ↑ Wizards RPG Team (2014). The Rise of Tiamat. (Wizards of the Coast), p. 76. ISBN 978-0786965657.
- ↑ Anthony Pryor (1995). Spellbound (Campaign Guide). (TSR, Inc), p. 7. ISBN 978-0786901395.
- ↑ Richard Lee Byers (April 2007). Unclean. (Wizards of the Coast), p. 27. ISBN 978-0-7869-4258-9.
- ↑ 9.0 9.1 
- ↑ Steven E. Schend (1999). Sea of Fallen Stars. (TSR, Inc), p. 15. ISBN 0-7869-1393-2.
- ↑ Richard Lee Byers (April 2007). Unclean. (Wizards of the Coast), p. 60. ISBN 978-0-7869-4258-9.
- ↑ Richard Lee Byers (April 2007). Unclean. (Wizards of the Coast), p. 104. ISBN 978-0-7869-4258-9.
- ↑ 13.0 13.1 13.2 Richard Lee Byers (April 2007). Unclean. (Wizards of the Coast), p. 108. ISBN 978-0-7869-4258-9.
- 4th Edition D&D
- Bruce R. Cordell, Ed Greenwood, Chris Sims (August 2008). Forgotten Realms Campaign Guide. (Wizards of the Coast), pp. 180–181. ISBN 978-0-7869-4924-3.
- Rob Heinsoo, Logan Bonner, Robert J. Schwalb (September 2008). Forgotten Realms Player's Guide. (Wizards of the Coast), pp. 122–123. ISBN 978-0-7869-4929-8.