Tikrit is the ancestral home city of Saddam Hussein's powerful clan and has enormous psychological importance to the regime.
The residents of the town, 165 km north-west of the capital, are intensely loyal to the Iraqi leader. It is home to members of a tight-knit ruling tribe and allied clansmen who have long been part of the regime's innermost circle.
It was near here that Saddam Hussein was born nearly 66 years ago. Military analysts have long predicted that the Iraqi leader, heavily outgunned by US and UK forces, may opt to make his last stand in Tikrit.
Many officers in the army and security services are Tikritis, as are a large number of Saddam Hussein's personal elite Special Republican Guards and the Fedayeen, the group of irregulars that has provided much of the resistance to coalition forces.
US intelligence officials believe that Tikrit may shed light on Saddam Hussein's alleged weapons of mass destruction programme. They believe that any weapons components he may possess could have been moved to private homes and underground bunkers in the town.
The Iraqi president has put a lot of money and resources into Tikrit, particularly after it was bombed by the allies during the 1991 Gulf War.
The town of more than 30,000 residents is no longer a provincial backwater. It now has big new mosques, wide modern roads, larger-than-life portraits and statues of the Iraqi ruler and one of his biggest and most sumptuous palaces.
One of Iraq's main oil refineries, Baiji, is located near Tikrit.
Saddam Hussein has traditionally celebrated his birthday - 28 April - in Tikrit. The occasions have been lavish affairs, with foreign dignitaries among the guests and tens of thousands of people parading through the streets in his honour.
Tikrit was recently put under the command of the president's younger son, Qusay, who was charged with protecting the heartland of the regime.
A division of the well-trained Republican Guard has been dug in around the city for weeks.
The town is symbolic to many Iraqis. Saladin, the great Arab leader who recaptured Jerusalem from the Crusaders, was born in Tikrit in 1138. Saladin, who was of Kurdish extraction, became Sultan of Egypt and champion of Islam.
According to a number of biographers of the Iraqi leader, Saladin is one of his role models.