Ground-based point measurements and the remotely sensed soil moisture data from the air-borne remote sensors (e.g., Polarimetric Scanning Radiometer, PSR, and Electronically Scanned Thinned Array Radiometer, ESTAR) have been used in various NASA field campaigns to investigate the spatio-temporal evolution and time–stable characteristics of soil moisture in different hydroclimatic regions. Past studies have helped understand how the various hydrologic controls like soil, topography, vegetation, and climate affect soil moisture dynamics across a large region and determine the time- stable locations which are representative of a field, footprint, or watershed. The purpose of this study is to conduct spatio-temporal analysis using data from soil moisture experiment 2005 (SMEX05) and investigate how the changes have occurred, if any, in the spatial pattern and time stable locations of soil moisture in the Walnut Creek watershed in Iowa. These results will be compared with those obtained from a previous campaign in 2002 (SMEX02) in the same field/watershed. We also studied the time stable features of soil moisture using data available from SGP97, SGP99 and SMEX03 field campaigns for the Little Washita watershed in Oklahoma organized over a span of about 7 years. The study will focus to determine the various physical controls responsible for soil moisture dynamics and time-stable characteristics over the long term. The findings will help designing long-term hydrologic monitoring networks in different hydroclimatic regions. Further investigation to locate the time stable remote sensing footprints are conducted for larger regions including the scaling relationship between point scale and pixel scale.