Iinozaka kofun group (飯野坂古墳群, Iinozaka kofun-gun) is cluster of Kofun period tumuli located in what is now the city of Natori, Miyagi Prefecture in the Tōhoku region of northern Japan.

The presence of an unusual number of large keyhole-shaped kofun located so close together drew attention, and the site received protection by the central government as a National Historic Site in 1976.

From the shape and construction of the mounds and from pot-shaped haniwa which have been recovered, the tombs are believed to date from the 4th century AD.

The site was endangered by the expansion of nearby housing developments in the early 1970s., but the presence of so many Zenpō-kōhō-fun [ja] in one location is unique, and the site received protection as a National Historic Site, It is about a 20-minute walk from Natori Station on the JR East Tōhoku Main Line.

Although the site is open to the public, there are no facilities and some of the kofun are covered with trees and dense undergrowth.