The frontal lobe is located in the front portion of the brain and is separated from other neighboring lobes by sulci. The frontal and parietal lobes are separated by the central sulcus. The frontal and temporal lobes are separated by the lateral sulcus. The location of the frontal lobe is indicated in the image below.
By Anatomography - en:Anatomography (setting page of this image), CC BY-SA 2.1 jp, Link
The frontal lobe has many functions that focus on reasoning, motor skills, higher level cognition and expressive language. More specifically, the frontal lobe is concerned with the following:
A man names Phineas Gage was a responsible, hard-working railway worker in 1848 until an accident caused a rail rod to go through his left eye into and through his frontal lobe. Miraculously, he survived, but because the rod impailed his frontal lobe, there were affects from the incident. One function of the frontal lobe is personality, and this is exactly what was affected by the rail rod's implantation in his brain. After the accident, he was more disrespectful, foulmouthed and had difficulty carrying out plans. This was drastically different to the personality he had before the incident.
Damage to the frontal lobe could lead to: