Although several studies have examined the spatial and rank stability of soil moisture at the surface layer (0-5cm) with the purpose of estimating large scale mean soil moisture, the integration of the rank stability of profile (0-60cm) soil moisture has not been fully considered. This research combines the rank stability at the surface and profile soil moisture to estimate large scale average soil moisture for better representation of the subsurface hydrology. The research is part of the Cloud and Land Surface Interaction Campaign 2007 (CLASIC07) remote sensing experiment with various combinations of soil types, vegetations, and management practices. Daily surface and profile soil moisture were measured with Theta and Time Domain Reflectometry (TDR) probes, respectively, in one winter wheat field and one pasture within the Little Washita River Experimental Watershed and two fields of irrigated crops within the Upper Washita River Watershed at 800 m x 800 m scale. The results of this research address whether the Rank Stable Sites (RSS) determined for surface and profile soil moisture are the same within a given area, and illustrate how RSS can be best employed in a surface soil moisture data assimilation scheme to better estimate soil moisture dynamics over large areas.