Free fishing derbies are held annually at Mammoth, Northmoreland and Twin Lakes Parks from 8:00 a.m. - 1:00 p.m. Registration is required and free of charge. All youth participants will receive a door prize upon registration. Trophies and prizes are awarded to both adults and youth. All participants ages 16 and older must display a current fishing license. For more information, please call 724-830-3959.