The Houston Zoo is a 55-acre zoological park located within Hermann Park in Houston, Texas, United States. The zoo houses over 6,000 animals from more than 900 species. It receives around 2 million visitors each year and is the second most visited zoo in the United States, surpassed only by the San Diego Zoo. It is accredited by the Associa…The Houston Zoo is a 55-acre zoological park located within Hermann Park in Houston, Texas, United States. The zoo houses over 6,000 animals from more than 900 species. It receives around 2 million visitors each year and is the second most visited zoo in the United States, surpassed only by the San Diego Zoo. It is accredited by the Association of Zoos and Aquariums.