Article: The Kuru kingdom was the first state-level society of the Vedic period, corresponding to the beginning of the Iron Age in northwestern India, around 1200 – 800 BCE, as well as with the composition of the Atharvaveda (the first Indian text to mention iron, as śyāma ayas, literally "black metal"). The Kuru state organized the Vedic hymns into collections, and developed the orthodox srauta ritual to uphold the social order. When the Kuru kingdom declined, the center of Vedic culture shifted to their eastern neighbours, the Panchala kingdom. The archaeological Painted Grey Ware culture, which flourished in the Haryana and western Uttar Pradesh regions of northern India from about 1100 to 600 BCE, is believed to correspond to the Kuru and Panchala kingdoms.

Now answer this question: What was the first state size society in the Vedic period?
Kuru kingdom