A special load forecast is a forecast of the future locations and magnitudes of electric load within a utility's service territory. Such forecasts are a necessary part of power delivery system planning. This paper presents a comprehensive review of spatial load forecasting techniques. A discussion of planning needs, uncertainty, spatial growth character, and forecasting error focuses attention on the essential qualities of a spatial forecast. The various approaches to forecasting are then reviewed, compared, and evaluated on a uniform basis. Emphasis is on the use of two-dimensional signal theory as a uniform framework for analysis of load, growth, error, and forecast model bahavior.