SMERGE Version 2.0 (September 11, 2019):

SMERGE data product page
Online access via HTTPS
Open-source Project for a Network Data Access Protocol (OPeNDAP) access
Access via NASA Earthdata Search Client
Visualize and analyze via NASA GES-DISC Interactive Online Visualization ANd aNalysis Interface (Giovanni)
SMERGE Readme document
Related Products:
LPRM_AMSRE_D_RZSM3: AMSR-E/Aqua root zone soil moisture (LPRM) L3 1 day 25 km x 25 km descending and 2-Layer Palmer Water Balance Model V001
Monthly County Data:
• Ogallala Aquifer Counties
• Southwest US Counties
 • Northwest US Counties