[3][4] The Musashi Provincial Capital ruins are located in the Miyamachi neighborhood of Fuchū, at the edge of a cliff formed by the Tama River, with the site currently occupied by the Ōkunitama Shrine.

The surrounding area contains many Kofun period remains, and from the late 7th to late 8th century, the population of an area 2.4 kilometers east-to-west by 1.2 kilometers north-to-south of this shrine had a massive population growth, with the traces of more than 4000 pit dwellings having been discovered under what is now the center of Fuchū city.

[5] Per an archaeological excavation of the shrine precincts and the surrounding area, the layout of structures corresponding to that of the semi-standardized format for a government office complex was found.

The Wamyō Ruijushō from 935 AD states only that the provincial capital of Musashi was in "Tama County" and does not give the exact location.

[5] Excavated artifacts include the names of 19 of the 21 Musashi counties written on tiles and rocks with a spatula, engraving, and ink.