Two separate two-hour nature discovery sessions for children ages 6 to 10 will be offered Saturday and Oct. 5 in Cranberry Township Community Park. The first session, “Senses,” is intended to help participants raise their awareness of the world around them. The second, “Wildlife Habitats,” will focus on meeting the environmental challenges facing local wildlife. Register in person at the Parks & Recreation customer service desk, by phone at 724-776-4806, Ext. 1129, or online at cranberrytownship.org/programs. The fee for each session is $15 for Cranberry residents and $20 for nonresidents.

Bartramian Audubon Society's wildlife sanctuaries will be the site of expert-led field trips. A trip to West Park in New Castle is set for Oct. 5. Trips are free and residents may participate in any or all of them. Trips start at 8:30 a.m. Contact Gene Wilhelm at 724-794-2434 or genewilhelm@aol.com.

Jennings Environmental Education Center, Route 528, Brady Township, will host the 20th annual National Public Lands Day from 9 a.m. to 1 p.m. Saturday. Registration is necessary. Call 724-794-6011 or visit www.apps.dcnr.state.pa.us/Calendar/list.asp. “Eating Green, Eating Wild!” will take place from 1 to 4 p.m. Oct. 5. The program is designed for people age 16 and older. Registration is required by Monday.

Moraine State Park will show a historic oil well in operation on Park Road from 10 a.m. to 4 p.m. Oct. 12. Call 724-368-8811.

McConnells Mill State Park in Slippery Rock Township, Lawrence County, hosts the 21st annual Heritage Festival from 11 a.m. to 6 p.m. Saturday and Sunday. The festival celebrates the operational time period of the gristmill from 1852 to 1928. Costumed vendors will display crafts inspired by this time. Bluegrass music, a Civil War encampment and free tours of the mill will be offered. The mill is open from 11 a.m. to 4 p.m. Fridays, Saturdays and Sundays. Tours, which last about 45 minutes, are available at 1 and 3 p.m. Call 724-368-3612.McKeever Environmental Learning Center, 55 McKeever Lane, Sandy Lake, will host the 11th annual Nature Art Show from 6 to 9 p.m. Friday, 10 a.m. to 6 p.m. Saturday and noon to 4 p.m. Sunday. Admission is free. Call 724-376-1000 or visit www.mckeever.org.