The project was undertaken to determine an offshore region in the western basin of Lake Erie using the statistical technique of clustering. The region when sampled during surveillance/monitoring programs would provide information on annual open lake water quality and data for long term trend analysis. Defining a representative offshore region in the western basin was more complex than for the other basins due to the shallowness of the western basin, resulting in extensive sediment/water column interactions, particularly during storm activity. The initial phase of the program was devoted to an extensive inventory of the STORET data base to determine the variables having the most consistent quality and quantity for utilization in multi-variable clustering. Five variables were selected for the multi-variable clustering routine: total phosphorus, total dissolved phosphorus, turbidity, chlorophyll and chloride. The resulting offshore representative region was then sub-clustered to determine the number of stations (N=5) needed during future sampling programs. The minimum number of surveys needed annually is seven.