| Named By: | Genus created by Frederick W. True in 1908. Type species of Z. kochii named by Remington Kellogg in 1936 |
| Time Period: | Late Eocene |
| Location: | Especially well known from the Eastern United States, but likely had a broader distribution in life |
| Size: | Body 6 meters long, Skull 1 meter long |
| Diet: | Carnivore |
| Fossil(s): | Multiple specimens |
| Classification: | | Chordata | Mammalia | Cetacea | Archaeoceti | Basilosauridae | |
| Also known as: | | Zeuglodon brachyspondylus minor | Zeuglodon hydrarchos | Zeuglodon hydrarchus | Zygorhiza brachyspondylus | Zygorhiza brachyspondylus minor | Zygorhiza minor | |
Zygorhiza ("Yoke-Root") is an extinct genus of basilosaurid early whale known from the Late Eocene (Priabonian, 38-34 Ma) of Louisiana, Alabama, and Mississippi, United States, and the Bortonian (43-37 Ma on the New Zealand geologic time scale) to the late Eocene of New Zealand (43 to 33.9 million years ago). Specimens reported from Europe are considered Dorudontinae incertae sedis.
Zygorhiza kochii is the state fossil of Mississippi. The mounted specimen in the Mississippi Museum of Natural Science in Jackson is commonly referred to as "Ziggy".