Abu Dhabi is the capital city of the UAE and the largest of the seven emirates that comprise the United Arab Emirates and was also the largest of the former Trucial States. and the second-most populous city of the United Arab Emirates (after Dubai).
It is also the location where Garfield repeatedly tries to send Nermal to (and actually doing so once). The reason for this is because the city of Abu Dhabi, and the majority of UAE, has a large amount of stray cats. The phrase "Abu Dhabi is where all the cute kittens go" is sometimes used in the comic. One strip had Garfield himself trying to get there, attempting to thumb a ride with the sign "Abu Dhabi" after learning of Jon's plans to invite his cousin and their children over. Another time Garfield himself wound up in Abu Dhabi.