The Eemian (also called the last interglacial, Sangamonian Stage, Ipswichian, Mikulin, Kaydaky, penultimate interglacial, Valdivia or Riss-Würm) was the interglacial period which began about 130,000 years ago at the end of the Penultimate Glacial Period and ended about 115,000 years ago at the beginning of the Last Glacial Period. It corresponds to Marine Isotope Stage 5e. Although sometimes referred to as the "last interglacial" (in the "most recent previous" sense of "last"), it was the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day (having followed the last glacial period). The prevailing Eemian climate was, on average, around 1 to 2 degrees Celsius (1.8 to 3.6 Fahrenheit) warmer than that of the Holocene. During the Eemian, the proportion of in the atmosphere was about 280 parts per million.
The Eemian is known as the Ipswichian in the UK, the Mikulin interglacial in Russia, the Valdivia interglacial in Chile and the Riss-Würm interglacial in the Alps. Depending on how a specific publication defines the Sangamonian Stage of North America, the Eemian is equivalent to either all or part of it.
The period falls into the Middle Paleolithic and is of some interest for the evolution of anatomically modern humans, who were present in Western Asia (Skhul and Qafzeh hominins) as well as in Southern Africa by this time, representing the earliest split of modern human populations that persists to the present time (associated with mitochondrial haplogroup L0).
The Eemian climate is believed to have been warmer than the current Holocene. Changes in the Earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as Milankovitch cycles, probably led to greater seasonal temperature variations in the Northern Hemisphere. During the northern summer, temperatures in the Arctic region were about 2-4 °C higher than in 2011. The warmest peak of the Eemian was around 125,000 years ago, when forests reached as far north as North Cape, Norway (which is now tundra) well above the Arctic Circle at .