PA 829 begins at an intersection with
PA 655 in the community of Knightsville in
Cass Township, heading west on a two-lane undivided road. The route runs through forested areas with some fields across a gap in Clear Ridge, curving to the north into a narrow agricultural valley. The road passes through an area of woods before coming into more farmland with some homes. At this point, PA 829 turns west and begins to ascend forested
Sideling Hill, curving southwest and then northwest as it crosses the hill. After descending Sideling Hill, the route enters the Trough Creek Valley and heads north into the borough of
Cassville and becomes Walnut Street, passing homes. Farther north, the road becomes Water Street and heads back into Cass Township, passing through agricultural areas with some residences and becoming an unnamed road. PA 829 curves to then north-northeast and runs through more areas of farms and woods with occasional homes. The route enters
Union Township and passes through
Calvin. The road continues northeast through more rural areas of the valley, passing through Colfax. Past here, PA 829 becomes Trough Creek Valley Road and heads into forests, crossing Sideling Hill again. After crossing the hill, the route continues through forests and crosses the
Juniata River. At this point, PA 829 heads into
Henderson Township and runs through rural areas of homes, crossing
Norfolk Southern's
Pittsburgh Line before ending at
US 22. ==History==