Ariyalur (Tamil: [aɾijaluːɾ]) is a town and district headquarters of Ariyalur district in the South Indian state of Tamil Nadu and is rich in limestone, surrounded with seven cement factories and two sugar factories.

Ariyalur comes under the Ariyalur assembly constituency which elects a member to the Tamil Nadu Legislative Assembly once every five years and it is a part of the Chidambaram constituency which elects its Member of Parliament (MP) once in five years.

Roadways are the major mode of transportation to the town and it also has rail connectivity which acts as a main station after Tiruchirappalli junction.

Mohammed Ali annexed the two palayams of Ariyalur and Udayarpalayam located with troops were in the Ariyalur district on the grounds of default in the payment of Tributes and failure to assist him in quelling the rebellion of Yusuf Khan.

In November 1764, Mohammed Ali represented the issue to Madras Council and obtained military assistance on 3 January 1765.

The annexation of the palayam gave the Navab uninterrupted possession of all his territories extending Arcot to Tiruchirapalli.

The history followed was a power struggle between Hyder Ali and later Tipu Sultan with the British.

Temperatures are hot to sweltering throughout the year, and especially unpleasant during the wet season under the northeast monsoon from October to December.

The rain shadow of the Western Ghats means that Ariyalur receives very limited rainfall during the southwest monsoon, but the city is likewise too far inland to receive sufficient northeast monsoon rainfall to be a tropical wet and dry climate.

One private sugar factory near Keelapalur is functioning in the district with a capacity of crushing 3,000 Tonnes per day.

The functions of the municipality is devolved into six departments: General, Engineering, Revenue, Public Health, Town planning and the Computer Wing.

[14][15] The current Member of Legislative Assembly (MLA) of the constituency since 2021 is K. Chinnappa from the DMK Party.

[21] Water supply is provided by the municipality of Ariyalur from Kollidam river through three schemes with head works of two of them located at Thirumanur.

In the period 2010–2011, a total of 2.3 million litres of water was supplied everyday for households in the town.

[22] About 11 metric tonnes of solid waste are collected from Ariyalur every day by door-to-door collection out of the 15 metric tonnes generated and subsequently the source segregation and dumping is carried out by the sanitary department of the municipality.

The Tamil Nadu State Transport Corporation operates daily services connecting various cities to Ariyalur.

[30] Ariyalur railway station is located on the line between the state capital Chennai and Trichy and is well connected by rail to major towns like Madurai and Tirunelveli.