McGuinness, who resigned as Northern Ireland's deputy first minister in January, died on Tuesday aged 66.
The Irish flag of green, white and orange -- a traditional symbol of the aspiration for an Irish Republic and an act of defiance against British rule -- adorned his coffin as it was carried out of his home in his native Derry in Northern Ireland.
The flag also flew from lampposts and windowsills in the streets of the nationalist Bogside district where McGuinness lived in a modest terraced house in the shadow of the 17th-century walls that dominate the city and were once a symbol of British rule.
He was hailed by many as a peacemaker in later life who played an instrumental role in the 1998 Good Friday Agreement which largely brought to an end a conflict in which around 3,500 people were killed.
But relatives of the victims of IRA bombs said they could not forgive him for his previous actions and British lawmaker Norman Tebbit, whose wife was left permanently disabled from the 1984 Brighton Hotel bombing called him a "coward".
McGuinness's coffin was carried through areas where he rose to prominence during the civil rights campaign of the late 1960s when Catholic nationalists demanded equality in a regime in which they considered themselves second-class citizens.
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In the following years he would rise through the ranks of a resurgent IRA to be regarded as the most dangerous of opponents in a guerilla campaign that would last a further three decades.
In a reminder how far Northern Ireland's society has changed, there was no ritual volley of shots over his coffin or visible security presence as would have been the case for a self-proclaimed "proud IRA volunteer" during the conflict.
Former US president Bill Clinton and former British prime minister Tony Blair attended the funeral, as well as Irish President Michael D Higgins and Irish Prime Minister Enda Kenny.
Derry resident John Coyle, 68, described McGuinness's death as "a huge setback for the city", describing him as "irreplaceable".
