This paper introduces a series of papers on the ecology, social organisation and behaviour of populations of sympatric macropods (Macropodoidea : Marsupialia) in north-eastern New South Wales. The study site, in the valley of Wallaby Creek, covers partly tree-cleared cattle-grazed pastures and also wet and dry forest communities; 10 species of macropods live there. The valley has a moderately high rainfall (1023 mm per annum), falling predominately in summer, and an equable climate of cool winters and warm summers. Soils derived from sedimentary and basaltic rocks and alluvium support naturally diverse plant associations further diversified by clearing and establishment of pasture and weed species. Macropods favouring open country occupy the pastures, which can also be used by cover-dependent species where pasture abuts forest or remnant patches of cover. Composition of the macropod community has changed since development of the pasture zone. Dingoes, major predators of some of the macropods, are abundant, and all exotic mammals other than cattle are rare. Populations of two of the macropod species are habituated to approach by observers, and close observation, on foot, of undisturbed animals has become our common study technique. A 1-ha grid has been established over 3.7 km2 of the study site to facilitate exact location of animals and observations. The suitability of the macropod populations for this kind of study results from the attitudes of the landholders.