Mackeyville is an unincorporated community in Clinton County, Pennsylvania, United States. The community is 5.8 miles (9.3 km) south of Lock Haven. Mackeyville has a post office with ZIP code 17750. Mackeyville is located near the eastern terminus of Nittany Valley. Fishing Creek runs along the eastern edge of town center head south to north. Fishing creek is a free limestone stream and parts of it are designated trophy trout stream.