Free Outdoor Discoveryprograms, hosted by the Butler County Parks and Recreation Department, will take place Thursday nights at Alameda Park. A program about geocaching is planned for 7 p.m. today in the Carousel Shelter. There is no program scheduled for July 4. Call 724-284-5383.

Moraine State Park will be the site of a program about Fireflies! from 8 to 9:30 p.m. Friday. Participants can find out about the lives of fireflies and how people can help scientists by counting and observing fireflies in their backyards. The program will take place at the Lakeview Beach picnic area on the North Shore. Fish for Free is planned for 7 to 9:30 a.m. July 4. Anyone can fish in Lake Arthur without a fishing license. Call 724-368-8811.

McConnells Mill State Park in Slippery Rock Township, just over the county line into Lawrence County off Route 422, will present a Hell’s Hollow Industrial History Hike from 10 to 11:30 a.m. July 6. Hikers will join the park naturalist for a leisurely walk along a trail to learn about the iron smelting, charcoal making and lime processing that took place there. Meet at the Hell’s Hollow parking lot. The historic gristmill is open from 11 a.m. to 4 p.m. Fridays, Saturdays and Sundays through October. Interpretive tours of the mill, which last about 45 minutes, will be available at 1 and 3 p.m. Additional tours for groups may be scheduled by calling 724 368-3612. Admission and parking are free.