Outspoken former Kakamega Senator Boni Khalwale on Friday returned to Nabongo grounds to mobilise residents for Saturday's rally.
Last week, police evicted Khalwale from the grounds after it was declared out of bounds by the authorities from the region.
The region was simultaneously hosting the Building Bridges Initiative rally in Kakamega town, around 100 KM from Mumias.
Khalwale, also a former Ikolomani MP, accused the state of intimidation as his team was chased out of the venue.
But on Friday, Khalwale inspected the grounds ahead of Saturday's rally, which he has insisted that will talk about economic challenges at the region.
"Now at Nabongo grounds. Curtain raiser for tomorrow's Western Economic Forum," he tweeted.
"Mobilization for tomorrow's Western Economic Forum in Mumias. Now at Makunga," added Khalwale.
Accompanying Khalwale were Sirisia MP John Waluke and former minister Rashid Echesa, who was also chased away last Saturday from Nabongo.
National Assembly Majority Whip Benjamin Washiali is expected to lead the rally on Saturday. He had avoided the venue last week.
The meeting is viewed as anti-BBI, with the organisers leaning towards Deputy President William Ruto, who has often had reservations about the campaigns.