The former Governor of Anambra State is the flagbearer of the Labour Party (LP).
Popularly known as Obidients, his followers shut down some major roads in the Central Area, including the Federal Secretariat, and others.
The walk by the citizens, in their thousands, caused gridlock at some locations in the nation’s capital.
In a tweet, Obi, currently in Kano State for a function, noted that he was following the march.
“From Kano, I am watching the Obidients gathered in Abuja and exercising their Constitutional rights to peaceful assembly.
“I salute you all. I appreciate you all. God bless you all and God bless the Federal Republic of Nigeria”, he wrote.
The supporters also gathered at the City Gate built about 30 years ago to commemorate the movement of the seat of power from Lagos.
The monument is the ceremonial entrance to the nation’s capital. Rallies for Obi are continuing across the country.
More is expected after the Independent National Electoral Commission (INEC) lifts the ban on political campaign next week.