A substantially enriched mammalian hepatic liver engrafting cell population is provided. Methods are provided for the isolation and culture of this liver engrafting cell, for example, a cell population containing human liver engrafting cells wherein at least one cell in the population is HLAlow/neg; and expresses at least one marker selected from the group consisting of albumin; 5E12; Ep-Cam; CD49f; and E-Cadherin. The progenitor cells are obtained from a variety of sources, including fetal and adult tissues. The cells are useful in transplantation, for experimental evaluation, and as a source of lineage and cell specific products, including mRNA species useful in identifying genes specifically expressed in these cells, and as targets for the discovery of factors or molecules that can affect them.