Singh's appointment was made by the party high-command, state Congress chief spokesman Mathuradutt Joshi said.
A former minister, Singh replaces Kishore Upadhayay whose tenure comes to an end next month.
Congratulating Singh on his appointment, the outgoing Uttarakhand Congress chief expressed hope that the new leadership will strengthen the party in the state.
He said he will extend all his cooperation to the party's new president and thanked all the party workers and office bearers for their cooperating with him during his three-year tenure.