This volume of Special Publication deals with the disposition and geological characteristics of various lithostratigraphic units and their tectonic framework of the Siwalik Group exposed in the Northwest Himalaya, India along with enormous amount of new geological data. The Standard Reference Sections (SRS), proposed by different workers for each Formation of the Siwalik Group as exposed in the Indian part have been included in this volume. The SRS of the Lower and Middle Siwalik subgroups are proposed along the Samba-Mansar-Ramnagar road section while for the Upper Siwalik Subgroup are proposed around northeast of Chandigarh along Nada SahebMorani road and Dhanaura-Haripr-Kalar road sections in Haryana.