Westmark is an unincorporated community in Phelps County, Nebraska, United States. Westmark is northeast of Bertrand and northwest of Holdrege, the county seat of Phelps County. History A post office was established at Westmark in 1879, and remained in operation until it was discontinued in 1903. Westmark was likely named for a pioneer settler. References Unincorporated communities in Phelps County, Nebraska Unincorporated communities in Nebraska