It was founded in 1962, through a merger of Swatantra Dal, Rajya Praja Sammelan, and dissidents of the then-dominant parties, Sikkim State Congress and Sikkim National Party.

The SNC was formed to be a party representing all ethnic groups in Sikkim, as the previously dominating parties were divided on ethnic lines.

It opposed the monarchy in Sikkim and worked for democratic reforms.

In April 1973, Sikkim Janata Congress merged with SNC.

After the merger of Sikkim with India in 1975, the party merged with the Indian National Congress.