 Path 66 consists of the northernmost segment of TANC's 500 kV line from Captain Jack substation to Tracy substation in California's Central Valley.Leaving Captain Jack substation, the line first heads southeast as a single-circuit line and runs parallel with the other two 500 kV lines across the Modoc Plateau.It then turns west and climbs in elevation and reaches its highest point near Grizzly Peak at about .