Busia County has become the fourth county to pass the Building Bridges Initiative (BBI) referendum Bill after Siaya, Homa Bay and Kisumu.
The Busia county assembly voted unanimously in support of the Bill during a session on Tuesday morning.
In an unrelated incident, the West Pokot county assembly was also scheduled to deliberate on the Bill on Tuesday.
The session was attended by Governor John Lonyangapuo and Pokot South MP David Pkosing.
BBI Secretariat co-chair Dennis Waweru, in a statement last week noted that up to 35 counties were expected to pass the bill.
He added that the country should anticipate a referendum in June 2021.
Baringo county assembly made history by becoming the first county to reject the bill.