Walker is a city in Vernon County, Missouri, United States. The population was 199 at the 2020 census. Walker had its start when the railroad w…Walker is a city in Vernon County, Missouri, United States. The population was 199 at the 2020 census. Walker had its start when the railroad was extended to that point. The town site was platted in 1870. The city was named for Hiram F. Walker, an early resident. A post office has been in operation at Walker since 1871. The city was incorporated in 1886.