In the old era, several cities were important centers of Jain population, culture, and learning. Some of these cities include:

1. Pataliputra (modern Patna) – The capital of ancient Magadha, Pataliputra was a major center for Jainism, especially during the time of Lord Mahavira.

1. Rajagriha (Rajgir) – Closely associated with Lord Mahavira and other Tirthankaras, Rajagriha was a significant place for Jain communities.

1. Vaishali – Considered the birthplace of Lord Mahavira, Vaishali had a substantial Jain population.

1. Ujjain – An important city in western India, Ujjain was renowned for its Jain temples and learned acharyas.

1. Mathura – Known as a prominent Jain center, many ancient Jain inscriptions and idols have been found here.

1. Shravanabelagola – Located in Karnataka, this became a major Jain pilgrimage center, especially during the later centuries.

1. Girnar (Junagadh) – Home to ancient Jain temples and inscriptions, Girnar was a significant site for Jain pilgrimage.

1. Pawapuri – The place where Lord Mahavira attained nirvana, Pawapuri was an important city for Jains.

1. Kausambi – Another ancient city with a notable Jain population and archaeological remains.

1. Champapuri (Champanagar) – Also associated with Mahavira and early Jainism.

Many other cities and regions, such as Taxila, Vallabhi, and Vidisha, also had vibrant Jain communities during different periods of history. Jainism has flourished in both northern and southern India throughout the centuries, with its population centers shifting according to historical, political, and economic changes.