Cudahy is a city located in southeastern Los Angeles County, California, United States. Cudahy has one of the highest population densities of …Cudahy is a city located in southeastern Los Angeles County, California, United States. Cudahy has one of the highest population densities of any incorporated city in the United States. It is part of the Gateway Cities region and had a population of 23,805 as of the 2010 U.S. Census.