Commonly known as just 'Sumacs' where I'm from, these can grow from a small shrub into a sizeable tree.
Staghorn sumac or Rhus typhina grows along the sides of roads and trails, open fields and anywhere that it can get sufficient light and water. By late July and August the fruits - conical clusters of small red drupes at the terminal end of a branch.
The leaves are long, finely serrated, alternate, with a fuzzy base of the stem and have between 9-31 leaflets. The plant forms clonal colonies, reproducing by underground shoots and forming dense clusters. It's unlikely to find just one sumac tree growing alone. Often these grow for long stretches alongside a trail or road.
A dense thicket of sumacs offer lots of shade, but can be hard to pass through. The fruits were used by native peoples of North America to make a tangy lemonade-style drink by soaking them in water. Rich in vitamin C, the pink lemonade made from these is pretty good tasting, in my opinion.
The leaves turn a fiery red in autumn and are spectacular to see when a hillside is covered in them. Next time you see the ubiquitous shrubby tree with red fuzzy fruits that persist late into the season, you'll know what you're looking at - sumac.