Westmark, NebraskaWestmark is an unincorporated community in Phelps [County, Nebraska|Phelps County], Nebraska, United States. Westmark is northeast of Bertrand and northwest of Holdrege, the county seat of Phelps County.HistoryA 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.