ATAR SIṄGH SANDHĀṄVĀLĪĀ (d. 1844), son of Amīr Siṅgh, was a collateral of Mahārājā Raṇjīt Siṅgh. After the direct descendants of the Mahārājā, he, as the eldest of the Sandhāṅvālīā family, stood close to the throne. A daring soldier, Atar Siṅgh was a calculating and shrewd courtier. He took part in several trans-Indus campaigns in Peshāwar and Hazārā. After the death of General Harī Siṅgh Nalvā, he was considered to be the "champion of the Khālsā. " He carried the titles "Ujjal Dīdār [of immaculate appearance], Nirmal Buddh [of clear intelligence], Sardār-i-bā-Waqār [the Sardār with prestige], Kāsir-ul-Iqtadār [eagle of power], Sarwar-i-Garoh-i-Nāmdar [leader of the renowned group], Ālī Tabā' [of exalted nature], Shujā'-ud-Daulā [valour of the State], Sardār Atar Siṅgh Shamsher-i-Jaṅg Bahādur [the valiant sword of battle]. " But he was fickle-minded and ambitious. At Raṇjīt Siṅgh's death he refused to swear fealty either to Khaṛak Siṅgh or Nau Nihāl Siṅgh, and became an active partisan of the Ḍogrā faction at the court. Soon afterwards he changed sides and joined Kaṅvar Nau Nihāl Siṅgh's party against the Ḍogrā minister, Dhiān Siṅgh, and went to Ludhiāṇā to find in the British territory a possible substitute for the Wazīr. When both Khaṛak Siṅgh and Nau Nihāl Siṅgh died in November 1840, he endeavoured to raise a group which would check Ḍogrā dominance at the Darbār, and, at the same time, prevent the succession of Sher Siṅgh. The Sandhāṅvālīās became staunch supporters of Rāṇī Chand Kaur, and Atar Siṅgh Sandhāṅvālīā, who had led a force against Sher Siṅgh when he stormed the Lahore Fort in January 1841, had to flee when the Fort fell. Later feeling insecure in the Punjab, he took asylum in British territory at Thānesar along with his nephew, Ajīt Siṅgh. Both of them kept up an attitude of open hostility towards Mahārājā Sher Siṅgh who had since succeeded to the throne. They solicited British interference in favour of Rāṇī Chand Kaur, and wrote letters to the officers of the Khālsā army inciting them to rise against their sovereign. A mild flutter was caused at Fort William when Atar Siṅgh hobnobbed with Dost Muhammad Khān, the deposed Amīr of Afghanistan at Ludhiāṇā, to what purpose nobody could tell. However when, as a result of British mediation, a reconciliation was brought about between the Sandhāṅvālīās and Mahārājā Sher Siṅgh, they were pardoned and allowed to return to Lahore. But Atar Siṅgh refused to come back to the Punjab, and continued to conspire against the Mahārājā. When in September 1843, Mahārājā Sher Siṅgh was treacherously assassinated by Ajīt Siṅgh Sandhāṅvālīā and Lahiṇā Siṅgh Sandhāṅvālīā, Atar Siṅgh was at Ūnā. On hearing of the retribution which soon overtook both the Sandhāṅvālīā sardārs, he hastily fled to Thānesar before a column of troops sent by Hīrā Siṅgh could capture him.

        Atar Siṅgh lived in exile at Thānesar along with the few remnants, of the Sandhāṅvālīā family who had escaped destruction in 1843 - his son Kehar Siṅgh, and a nephew Raṇjodh Siṅgh, a brother of Ajīt Siṅgh. He nursed enmity against Hīrā Siṅgh and kept in touch with the disaffected elements in the Punjab. When in May 1844, Kaṅvar Pashaurā Siṅgh and Kaṅvar Kashmīrā Siṅgh revolted, he raised a small force and joined them at Nauraṅgābād after crossing the Sutlej, near Harīke. The Lahore Darbār protested to the British at Ludhiāṇā for allowing the rebels passage through their territory. A Sikh force 20, 000 strong under Mīāṅ Lābh Siṅgh and General Gulāb Siṅgh crossed the Sutlej and surrounded the ḍerā of Bhāī Bīr Siṅgh Naurāngābādī. However, the Lahore commanders, respecting the sanctity of Bhāī Bīr Siṅgh, repaired to his camp to bring about an amicable settlement. As negotiations were in progress, Atar Siṅgh flew into a rage and fatally stabbed General Gulāb Siṅgh with his dagger. The attendants of the General instantly fell upon Atar Siṅgh and hacked him to pieces. This was in May 1844.