The concept of soil tilth has many facets, ranging from the relatively simple effects of tillage to the physical condition of the soil created by integrating the effects of all physical, chemical, and biological processes occurring within a soil matrix. The objectives of this review are to examine historical perceptions of soil tilth, review research conducted to address soil tilth, and identify research needed to quantitatively understand soil tilth to improve management of our nation's soil and water resources. The four sections of the review trace the origin of the term, summarize research conducted prior to 1955, discuss research since 1955, and present some of the unsolved soil tilth research goals and needs. We believe the current Soil Science Society of America (SSSA) definition for soil tilth is too restrictive to accurately reflect this dynamic, multifaceted concept. Hence, a modified description of soil tilth is proposed to replace the current SSSA glossary definition. A new term, “tilth‐forming processes,” also is proposed and defined. Relationships between tilth and several soil and water management problems such as surface and groundwater quality, soil erosion, productivity, and long‐term sustainability are discussed.