to
Update
is a city in Linn County, Iowa, United States. The population was 750 at the 2000 census. It is part of the Cedar Rapids Metropolitan Statistical Area.
Near Walker, there are several guy-wired TV towers, all of them nearly 2000 feet tall.
According to the United States Census Bureau, the city has a total area of 0.7 square miles (1.8 km²), all of it land.