There is no classification of river and lake ice that simultaneously takes into account the history of ice formation, the structure of the ice cover, and the texture of the various ice types. Such fundamental information is a prerequisite to the determination and discussion of their physical and mechanical properties.The first part of this classification is a brief description of the formation and the physical properties of the three important ice layers making up the ice cover. The second aspect of the classification deals with the texture of various ice types.It is possible to determine certain meteorological conditions which have occurred during formation of primary ice from on-site observations and the study of ice profiles. Hydrodynamic information can be obtained from the study of secondary or superimposed ice. Presently, major events causing layers of frazil slush, congealed frazil slush, and drained snow ice can easily be recognized and interpreted.The evaluation and eventual prediction of the mechanical properties of the various ice types according to such a classification will be helpful in solving engineering and navigation problems.