The Mauryan pillar capital found at ________ is popularly known as the Lion Capital.

The correct answer is Sarnath.

The Mauryan pillar capital found at Sarnath is famously known as the Lion Capital of Ashoka. Built during the reign of the Mauryan Emperor Ashoka in the 3rd century BCE, this polished sandstone carving features four Asiatic lions standing back-to-back on an elaborate circular abacus.

The abacus itself is decorated with reliefs of an elephant, a galloping horse, a bull, and a lion, separated by intervening chariot wheels (Dharma Chakras). The wheel from this capital (the Ashoka Chakra) was adopted as the central motif of the national flag of India, and the Lion Capital itself is the National Emblem of India.