A TV over the fireplace is one of the most requested mounts and one of the easiest to get wrong. Three things decide whether it works: heat, height and the wall.
Heat
Fireplaces run warm, and heat is hard on a TV. The fix is to check the mantel temperature and the clearance, and where it runs hot, use a pull-down mount so the screen sits away from the heat when it is up. A mantel that stays cool with normal use is usually fine.
Height
Over a fireplace the TV often ends up too high, so you watch with your neck craned. A pull-down mount solves it by bringing the screen down and forward to eye level when you watch, then tucking it back up. If the mantel is low, a tilt mount can be enough. More on this in how high to mount a TV.
The wall
A fireplace wall is masonry, stone, tile or brick, not drywall. It needs the right masonry bit and anchors rated for the weight, drilled cleanly so the face does not crack. This is not a spot for drywall anchors.
Wires
Wires can usually be hidden here too, in the wall above the firebox or in a clean raceway on solid masonry. See how to hide TV wires.
Want it heat-checked, anchored into the stone and set at a comfortable angle? That is our over-fireplace mounting service.