Density Structure in Active Regions from Hinode/EIS

The Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode provides an excellent opportunity to study the physical plasma parameters in spatially resolved coronal features. In this paper we present the density structure in an active region at many different temperatures. The active region was rastered on May 01, 2007 with the 2^{''} slit. We find that the electron density is highest in the core of the active region where it exceeds log_{10} N_e = 10.5.