Walker is a city in Linn County, Iowa. The population was 688 at the 2020 census. It is part of the Cedar Rapids, Iowa metropolitan area. Walke…Walker is a city in Linn County, Iowa. The population was 688 at the 2020 census. It is part of the Cedar Rapids, Iowa metropolitan area. Walker began as an outgrowth of the Burlington, Cedar Rapids and Northern Railway. It was named in honor of W. W. Walker, chief engineer of the railroad.