Police said the fighting began after some members of the Pokomo community attacked Orma residents in a fight over pastureland, Standard Digital News reported.
Police said 31 women and 11 children were among the victims.
"The deaths occurred when Pokomos attacked Ormas in the area," police official Robert Kitur said. "It is a bad scene and officers have been dispatched there to ensure no more deaths and destruction of property."
Officials said an unknown number of people were injured and at least five dozen cows were hacked to death.
"It was massacre because they even killed animals which do not know what was happening. We are shocked because bodies are lying on the ground," one resident told the Standard Digital News in a telephone interview.
The fighting Wednesday followed an incident last week in which three Pokomo villagers were killed and six injured after an attack by Orma herdsmen.