NGC 4100 is a spiral galaxy with extended HII regions of the Hubble type (R ‘) SA (rs) bc in the constellation Great Bear in the Northern Star Sky , which is estimated to be 57 million light-years from the Milky Way .

The object was discovered in 1788 by William Herschel using his 18.7-inch telescope and later recorded by Johan Dreyer in his New General Catalog .