When an in ground firepit is mentioned, it usually means a permanent pit which is made inside the ground by digging a hole and then lining it up with the stones and pebbles. If you want to have one fire pit in your backyard, frontyard or outdoor porch, you must specify the area first because once the hole is dug, it will stay there forever. Changing the position of the fire pit would not be possible once the set up for an in ground pit is complete.
Whether you have an above ground fire pit or an in ground firepit in your front yard, it is suitable for bonfires, barbecues, heating purposes. The fuel sources are different depending on the personal choice and taste, there are simple wood burning fire pits, propane fire pits as well as gas fire pits. The gas can be linked to an in ground fire pit easily as a permanent heating solution without much expenses.
The above ground fire pits are lined by the stones, pebbles and concretes, they look nice in the landscape, they are also being made of ceramic, iron and metal for adding more aesthetics to the exterior. An in ground firepit usually is inside the ground, it looks better to have this outdoor fire pit as a permanent heating source during harsh winter weathers. To make this fire pit to merge with the exterior beauty, just arrange some nice and comfortable chairs around the pit. Invite your guests and have barbecue right on the fire which is available through the fire pit.
Some homeowners use stones only when they dig a hole into the ground for making an in ground firepit, the stones are extended few inches above the ground as well, to create a nice foundation. The use of rocks and bricks help insulate the fire from the soil, it also helps blocks the wind that stops the fire from burning. When you are sitting around an in-ground pit with the family members, the stone wall will reduce the air pressure towards the pit, helping the fire to burn constantly, you can add a grill top for cooking. A sunken firepit is another way of doing it, it can be removed, once it is removed you can resume using the open fire which is coming straight from the ground.
Reference: How to build an in ground fire pit