Elgeyo Marakwet County Assembly has rejected the Constitution Amendment, 2020 Bill.
Seventeen MCAs on Monday voted to reject the Bill, while 15 voted in support of it during a session chaired by speaker Kiplagat Sabulei.
The county becomes the third to reject the bill after Baringo and Nandi.
Elgeyo Marakwet Governor Alex Tolgos is chairman of the BBI process in Rift Valley and has been lobbying the MCSs to pass the Bill.
Uasin Gishu Assembly is also expected to vote on the bill.
The region is home to DP William Ruto and most MCAs are allied to him.
Ruto has previously said BBI is not a priority in a country ravaged by Covid-19. Most MCAs in the Rift Valley - Ruto's backyard - had pledged to shoot the Bill down but Kericho, West Pokot, Bommet, Turkana and Samburu approved it.
Nandi county assembly rejected the bill last Thursday. Ruto was in the area just a day later after they rejected the bill
In Elgeyo Marakwet, public participation was done last Friday.
Jubilee secretary-general Raphael Tuju had summoned 17 nominated MCAs from Uasin Gishu to party headquarters last week and told them the Bill must be passed.
