The town's population was estimated to be 145,332 in 1998. More than 99 % are Muslim. The town covered around 300 km² in the early 1990s. Rapid ad-hoc expansion of the town has caused severe and widespread environmental degradation, resulting in flash floods in 2001 that reportedly made several hundred families temporarily homeless.
A 1992 study by the University of Nice reported significant areas contaminated by industrial pollution, and growing squatter settlements on the periphery.
The region is predominantly one of agriculture. There is a large airfield with a tower and terminal, at Abdelhafid Boussouf. The town is not a tourist destination.
The province suffered massacres (the largest being the Sid El-Antri massacre in 1997), killings, and bombings during the Algerian Civil War, though less so than areas closer to Algiers. The Africa Institute reported in a May, 2004 monograph that Tahert's more "arid and mountainous landscape has facilitated terrorist activities". The MIPT Terrorism Knowledge Base reports that Tahert: "is a frequent site of attacks by the Salafist Group for Call and Combat (GSPC)". The GSPC is: "believed to have close ties to Osama bin Laden" (Paris AFX News Agency, Jul 13, 2005) and Abu Musab Al Zarqawi (Asharq Alaswat Jul 3 2005), and is reported to be active in Italy (Deutsche Welle, Jul 15 2005).
The province has been inhabited since ancient times, and there are numerous megalithic monuments.
The Jedars tombs near Tahert are evidence that the province was inhabited, from at least the 5th Century, by a tribe or tribes that could build in stone. According to the Encyclopaedia Britannica "Tiaret" article: "It was an Arab town of note in the 7th century, known as Tahart (“Lioness”)."
Tahert grew up as a site under the domination of petty Berber tribal kingdoms; the first of these being the Rustamids between 761 and 909 when Tahert served as the capital of the area. However, this capital may have been 10 km (6 or 7 miles) west of the present-day Tahert. It was first founded by Abd al-Rahman. Tahert was said to be relatively free-thinking and democratic, being a centre for scholarship that permitted a wide range of sects and movements - notably the Mu'tazilites - which came to trouble Sunni and Shiite followers alike. There were said to be Jews living in the area, until at least the 900s; including the scholar and doctor Judah ibn Quraysh who became the doctor to the emir of Fes.
Tahert occupies a strategic mountain pass at 3552 feet, and was thus a key to dominating the central Maghrib. Later, from the start of the 8th century, it was the key northern terminus of the West African slave-trading route. As such, it offered a lucrative income from taxes on the trade, and was a desirable prize.
From the year 911 Tahert was fought over by a number of tribes, being first captured by Massala ibn Habbus of the Miknasas in the year 911, in alliance with the Fatimids. Finally, in 933, it was in the hands of the Fatimids only. After 933 Tahert ceased to be the capital of a separate state. Most of the population was banished to Wargala and then escaped to the inhospitable M'Zab Valley. From 933 Tahert attracted many Khariji Muslim settlers from Iraq.
From 933 it was administered as part of the sultanate of Tlemcen, and in the 16th century fell to the Turks. In 1843 it fell to the French, after the French defeated Emir Abelkader. The modern town of Tahert is essentially French-built, around a French redoubt of 1845. The new town attracted many farmers and settlers from France, and the area flourished. A 200 km (122 mile) narrow gauge railway arrived in 1889, connecting the town to Mostaganem - today, this rail line is defunct.
Thirty kilometres (18 miles) S.S.W. of Tahert are the sepulchral monuments known as the Jedars. The name is given to a number of sepulchral monuments placed on hill-tops. A rectangular or square podium is in each case surmounted by a pyramid. The tombs date from the 5th to the 7th century, and lie in two distinct groups between Tiaret and Frenda.