Hobbits were an ancient mortal race. Although their exact origins are unknown, they were initially found in much of the north of Middle-earth and down the Vales of Anduin. At the start of the Third Age, Hobbits moved north and west. Most of their race eventually founded the land of the Shire in TA 1601 (Third Age).
Most Hobbits lived longer than Men, a race which they were clearly related to. The average lifespan of a Hobbit was 100 years, sometimes living until they were 130 years old. The time at which a young Hobbit matured and was accepted as an adult was 33, as compared to a Man's 21 years. Thus, a Hobbit 50 years old would only be middle-aged.
The most distinguishing feature of a Hobbit was their short stature. They were smaller than Dwarves and were usually between two and four feet in height. With the gradual passing of time, Hobbits became even shorter. By the Third Age, they were usually less than three feet tall. When they reached age 130, they had a bonus life time of 20 years, if they lived in peace and honor.