A method and apparatus for entering an address for a navigation system allows a user to easily and quickly select a key indicating the next character of the address. At the start of operation, the navigation system shows a full alpha-numeric keyboard. Once the next candidate characters are narrowed down to a certain degree, the navigation system shows a simplified keyboard with a limited number of keys on the monitor screen and highlights the next candidate characters on the simplified keyboard. The navigation system displays both the simplified keyboard and a street name list on the same screen. Since the keys of the limited number are arranged within a small space such as in the three-by-three manner, the user can easily point a cursor or other pointing device to the desired key.