The AFL-CIO says they sent a letter to Governor Lepage, asking the Department of Corrections reopen the facility and resume operations immediately.
The demand comes after a superior court judge found the Governor didn't have the authority last month when he ordered the prison closed and the inmates sent elsewhere.
The judge issued a temporary injunction saying Lepage needed legislative approval before making the move.
The workers are demanding their jobs be reinstated with full back pay and benefits.
They also want all the inmates who were transferred elsewhere to be returned.
Governor Lepage wants to close the facility to save money, but some lawmakers are against it and have been trying to find additional funds to keep the prison running.