From WikiPedia:
Chalco is a census-designated place (CDP) in northern Sarpy County, Nebraska, United States, and an adjacent suburb of Omaha, with La Vista located to the southeast. The population was 10,994 at the 2010 census.
From Nebraska Place Names (LILIAN LINDER FITZP A TRICK, A.M., 1925)
Chalco. Chalco is a village on the Chicago, Burlington, and Quincy railroad in the northern part of Sarpy county. There is a town and a lake, both named Chalco, situated twenty-five miles southeast of the city of Mexico. The word chalco is from the Greek chalkos, brass (so named from the color), referring to the native mineral or copper ore. Chalcocite is a native copper sulphide, a mineral with a black color and a metallic luster. Chalcopyrite or copper pyrites or yellow copper ore, is a common ore of copper, con- taining copper, iron, and sulphur. It is probable that the place in Mexico and the one in Nebraska derived their names either directly or indirectly from the presence or supposed presence of native copper ores. Chalco, Nebraska, is the only place so named in the United States.
