Soil moisture, despite its significant role in hydro-geomorphological and biogeochemical processes, is not well understood in many environments, particularly in developing nations with limited monitoring basins. This chapter describes a mode of soil moisture investigation in an ungauged catchment in southwestern Nigeria. The study first explained the rationale for soil moisture investigation in the study area which is typical of a data-dearth environment, due to poor monitoring technology and commitments. Consequently, examples of well-established stations around the world were first presented before the attempt to determine the spatial variability of soil moisture was reported. Reported here are the results of an assessment of soil moisture using open-source satellite data. The study also reports an assessment of the correlation of  specific vegetal change indices (such as land cover/use and the Normalized Difference Vegetation Index, or NDVI) with land surface temperature (LST) in the area. ArcGIS (version 10.3) was used to analyze the multidate Landsat 8 OLI (Operational Land Imager) data. The results showed that throughout the study period, average soil moisture (SMI) increased from 6.8 to 9.3%, demonstrating spatial homogeneity. The SMI correlated spatially with land cover and use, classifying forested areas as wetter than built-up areas and reducing wetness in proportion. Land surface temperature (LST) and the Normalized Difference Vegetation Index (NDVI) varied spatially in proportion to variations in land use/cover, indicating that these variations had a substantial effect on LST, SMI, and NDVI. The results of multiple regression analysis point to a complicated interaction among the three variables.